How to Hold it still the augmented (AR) Object at the center of Mobile Screen after detection?

Hello Unity3D-AR developers,

I am trying to do an AR app with Unity3d and vuforia for Android Mobile. In that, the augmented objects are shown OnTrackingFound. After the AR object is loaded I want it to be there even if we move the ARCamera out of ImageTarget. I tried commenting OnTrackingLost();

By doing this, the Augmented object is still there but, as we move the camera out of ImageTarget, the orientation and the position is not in center.

How to make the AR object center on the mobile screen when we move the camera out of ImageTarget??

Is there any way we could do this??

Thanks