How do I get a path to move with a 3D tracker?

Here is what I have so far: Lumia920 Flying Text - YouTube

What I'm trying to do in this video is to get the floating Lumia 920 to reflect off of the desk, but not the phone and not the taped part of the desk. I've been trying to apply a mask to a copy of the underlying footage, but there's no position options once I do that.

My method of getting what I have so far was to:

1. Track Camera on the underlying footage.

2. Choose a plane and set up the Lumia 920 text where I want it.

3. I have a couple of light layers.

4. For the reflection, I duplicated the Lumia 920 layer and played with the x-axis orientation. Then I decreased opacity to 15% and applied a fast blur.

How do I get that reflection to be masked in some areas and for the masks to move with the phone and taped part of desk?

Thanks!