Thanks for posting those instructions.

Hello people. I came accross your post and I thought I might put in my two cents. Maybe someone else will have the same problem and can come look here. i have been having the same problem and I managed to get it to work on mine. I went into the manifest and read through everything. For Prime[31] to work, you have to generate the AndroidManifest.xml file from the menu. What this then does (and please correct me where I go wrong), is completely overwrite the xml that you had there when you imported the prime[31]  plugin, inadvertently "killing" Vuforia.  Here is what I did, I went and looked at all the stuff Vuforia needed in its xml and added that to the one that Prime[31] had overwritten. 

Here is my code:

<?xml version="1.0" encoding="utf-8"?>
<manifest
    xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.qualcomm.QCARUnityPlayer"
    android:versionCode="1"
    android:versionName="1.0">
    <uses-sdk android:minSdkVersion="8" />
    <uses-feature android:name="android.hardware.camera" />
    <supports-screens
        android:smallScreens="true"
        android:normalScreens="true"
        android:largeScreens="true"
        android:anyDensity="true" />
        
    <application
		android:icon="@drawable/app_icon"
        android:label="@string/app_name"
        android:debuggable="true">
        <activity android:name="com.unity3d.player.UnityPlayerProxyActivity"
                  android:label="@string/app_name"
                  android:configChanges="fontScale|keyboard|keyboardHidden|locale|mnc|mcc|navigation|orientation|screenLayout|screenSize|smallestScreenSize|uiMode|touchscreen">
          
        </activity>
        <activity android:name="com.unity3d.player.UnityPlayerActivity"
                  android:label="@string/app_name"
                  android:configChanges="fontScale|keyboard|keyboardHidden|locale|mnc|mcc|navigation|orientation|screenLayout|screenSize|smallestScreenSize|uiMode|touchscreen">
        </activity>
        <activity android:name="com.unity3d.player.UnityPlayerNativeActivity"
                  android:label="@string/app_name"
                  android:configChanges="fontScale|keyboard|keyboardHidden|locale|mnc|mcc|navigation|orientation|screenLayout|screenSize|smallestScreenSize|uiMode|touchscreen">
            <meta-data android:name="android.app.lib_name" android:value="unity" />
            <meta-data android:name="unityplayer.ForwardNativeEventsToDalvik" android:value="true" />
        </activity>
        <activity android:name="com.unity3d.player.VideoPlayer"
                  android:label="@string/app_name"
                  android:screenOrientation="behind"
                  android:configChanges="fontScale|keyboard|keyboardHidden|locale|mnc|mcc|navigation|orientation|screenLayout|screenSize|smallestScreenSize|uiMode|touchscreen">
        </activity>
    
    
    <activity android:name="com.qualcomm.QCARUnityPlayer.QCARPlayerProxyActivity"
                  android:label="@string/app_name"
                  android:configChanges="fontScale|keyboard|keyboardHidden|locale|mnc|mcc|navigation|orientation|screenLayout|screenSize|smallestScreenSize|uiMode|touchscreen">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity android:name="com.qualcomm.QCARUnityPlayer.QCARPlayerActivity"
                  android:label="@string/app_name"
                  android:configChanges="fontScale|keyboard|keyboardHidden|locale|mnc|mcc|navigation|orientation|screenLayout|screenSize|smallestScreenSize|uiMode|touchscreen">
        </activity>
        <activity android:name="com.qualcomm.QCARUnityPlayer.QCARPlayerNativeActivity"
                  android:label="@string/app_name"
                  android:configChanges="fontScale|keyboard|keyboardHidden|locale|mnc|mcc|navigation|orientation|screenLayout|screenSize|smallestScreenSize|uiMode|touchscreen">
            <meta-data android:name="android.app.lib_name" android:value="unity" />
            <meta-data android:name="unityplayer.ForwardNativeEventsToDalvik" android:value="false" />
        </activity>
        <activity android:name="com.unity3d.player.VideoPlayer"
                  android:label="@string/app_name"
                  android:configChanges="fontScale|keyboard|keyboardHidden|locale|mnc|mcc|navigation|orientation|screenLayout|screenSize|smallestScreenSize|uiMode|touchscreen">
        </activity>

		    <activity android:name="com.prime31.EtceteraProxyActivity"></activity>
			<activity android:name="com.prime31.WebViewActivity" android:configChanges="orientation"></activity>
			<activity android:name="com.prime31.P31VideoPlayerActivity" android:configChanges="keyboard|keyboardHidden|orientation"></activity>
			<receiver android:name="com.prime31.AlarmManagerReceiver"></receiver>
</application>

	    <uses-permission android:name="android.permission.INTERNET"/>
	    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
		<uses-permission android:name="android.permission.GET_TASKS"/>
		<uses-permission android:name="android.permission.WAKE_LOCK" />
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
    <uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
 
    <uses-permission android:name="android.permission.CAMERA" />
    <uses-permission android:name="android.permission.READ_PHONE_STATE"/>

</manifest>

Please edit and correct if I have made mistakes or disregard if I have compkletely butchered it. :) 

Many Thanks,

Fish

I tried yours .. the AR camera is working and i can see the web view but I can't interact with it it looks like only rendering the web no mouse events occurs

<?xml version="1.0" encoding="utf-8"?>

<manifest

    xmlns:android="http://schemas.android.com/apk/res/android"

    package="com.qualcomm.QCARUnityPlayer"

    android:versionCode="1"

    android:versionName="1.0">

    <uses-sdk android:minSdkVersion="8" />

    <uses-feature android:name="android.hardware.camera" />

    <supports-screens

        android:smallScreens="true"

        android:normalScreens="true"

        android:largeScreens="true"

        android:anyDensity="true" />

    <uses-permission android:name="android.permission.WAKE_LOCK" />

    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

    <uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />

    <uses-permission android:name="android.permission.INTERNET" />

    <uses-permission android:name="android.permission.CAMERA" />

    <uses-permission android:name="android.permission.READ_PHONE_STATE"/>

    <application

android:icon="@drawable/app_icon"

        android:label="@string/app_name"

        android:theme="@android:style/Theme.NoTitleBar.Fullscreen"

        android:debuggable="false">

        <activity android:name="com.qualcomm.QCARUnityPlayer.QCARPlayerProxyActivity"

                  android:label="@string/app_name"

                  android:configChanges="fontScale|keyboard|keyboardHidden|locale|mnc|mcc|navigation|orientation|screenLayout|screenSize|smallestScreenSize|uiMode|touchscreen">

            <intent-filter>

                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />

            </intent-filter>

        </activity>

        <activity android:name="com.qualcomm.QCARUnityPlayer.QCARPlayerActivity"

                  android:label="@string/app_name"

                  android:configChanges="fontScale|keyboard|keyboardHidden|locale|mnc|mcc|navigation|orientation|screenLayout|screenSize|smallestScreenSize|uiMode|touchscreen">

        </activity>

        <activity android:name="com.qualcomm.QCARUnityPlayer.QCARPlayerNativeActivity"

                  android:label="@string/app_name"

                  android:configChanges="fontScale|keyboard|keyboardHidden|locale|mnc|mcc|navigation|orientation|screenLayout|screenSize|smallestScreenSize|uiMode|touchscreen">

            <meta-data android:name="android.app.lib_name" android:value="unity" />

            <meta-data android:name="unityplayer.ForwardNativeEventsToDalvik" android:value="false" />

        </activity>

        <activity android:name="com.unity3d.player.VideoPlayer"

                  android:label="@string/app_name"

                  android:configChanges="fontScale|keyboard|keyboardHidden|locale|mnc|mcc|navigation|orientation|screenLayout|screenSize|smallestScreenSize|uiMode|touchscreen">

        </activity>

<!-- ACTIVITIES -->

   <activity android:name="com.prime31.EtceteraProxyActivity"></activity>

<activity android:name="com.prime31.WebViewActivity" android:configChanges="orientation"></activity>

<activity android:name="com.prime31.P31VideoPlayerActivity" android:configChanges="keyboard|keyboardHidden|orientation"></activity>

        <receiver android:name="com.urbanairship.CoreReceiver">

            <intent-filter>

              <action android:name="android.intent.action.BOOT_COMPLETED" />

              <action android:name="android.intent.action.ACTION_SHUTDOWN" />

            </intent-filter>

        </receiver>

        <receiver android:name="com.urbanairship.push.c2dm.C2DMPushReceiver" android:permission="com.google.android.c2dm.permission.SEND">

          <intent-filter>

              <action android:name="com.google.android.c2dm.intent.RECEIVE" />

              <category android:name="com.gian.appmazinc" />

          </intent-filter>

          <intent-filter>

              <action android:name="com.google.android.c2dm.intent.REGISTRATION" />

              <category android:name="com.gian.appmazinc" />

          </intent-filter>

        </receiver>

        <service android:name="com.urbanairship.push.PushService" android:process=":com.urbanairship.push.process" />

<receiver android:name="com.prime31.P31UAIntentReceiver" />

<!-- META-DATA -->

    </application>

</manifest>

<!-- android:installLocation="preferExternal" -->

I'm not familiar w/ the Etcetera manifest, can you post a copy? Have you tried defining the manifests additively - i.e. to simply add the necessary permissions, etc., to the Vuforia manifest?