Use a Marker with Vuforia to initialize a Calibration for a HoloLens Scene

Hi

What I want:

A Marker, which should be the (0,0,0) point of my Scene, should be recognized with Vuforia in my scene and place an Object at this point and after that let HoloLens do the tracking work.

How Can I only let Vuforial do the initialize tracking and then let HoloLens do the rest?

What I did:

on Vuforia:

-Create a license

-Create a target database with a marker (with 5 star rating)

-Download the database unity package, startpoint.unitypackage

in Unity3D:

-Create a 3D project

-Import the HoloLens Mixed-Reality-Toolkit

-Delete everything in the Scene

-Apply MixedReality Project Settings: (target UWP, enable XR, build for direct3d, enable .net scripting backend, set default spatial mapping layer)

-Apply MixedReality Scene Settings: (Add mixed reality prefab cam, move camera to origin, add input manager, add default prefab cursor, update world space canvases)

-Apply MixedReality Capability Settings: (Microphone, Webcam, Spatial perciption, Internet Client)

Import Package: 

-Import the startpoint.unitypackage

Scene Objects: (the HoloLens Objects are already created... like SpatialMapping, DefaultCursor, InputManager, MixedRealityCamera)

-Create a ImageTarget Vuforia object

     -> In Image Target Behaviour Script settings: select startpoint Database,  and the right image target

-Create a simple Cube as a Child of the ImageTarget

-Create a Vuforia AR Camera (no changes were done)

Vuforia Configuration:

Global:

-Add App license key

-Check: Load Object Targets on Detection

Digital Eyewear:

-Device type: Digital Eyewear

-Device Config: HoloLens

Database:

-Selet the right Databse (startpoint)

Testing:

Running in Unity3D Player => The simple Cube is shown on the marker

Building Unity Project => Running on HoloLens => I see the normal Objects, I see the Spatial Mapping.. But when I look at the Marker, I don't see the Cube which I placed as a child to the Target Image.

What am doing wrong? How Can I only let Vuforial do the initialize tracking and then let HoloLens do the rest?