I have sorted this problem by moving the inside mask manually but I was thinking there must be an easier and quicker way of doing this using tracking data.
I have an ipad thats being held and its got some green content on the screen (im chroma keying the scene)
I get a good rotational track on the edges of the screen and have got the tracking data perfect.
I have applied it to a null with a mask in a separate adjustment layer parented to the null.
The mask in the adjustment layer moves perfectly with the footage but its not "on" the footage layer, hence I cannot select it from the keylight drop down to choose the inside mask...
I have done it manually for this shot but I would love to know the method to do this properly,