[FMX] Problem: loadMovie with animated mask

Hello all. I’ve come seeking advice.

See, I’ve got this interactive storybook that loads each page from separate swf files into a movie clip. The movie clip is masked, and with every turn of the page, the mask changes shape so it looks like the pages are covering up the content. Once the page turn is complete, we’re supposed to be left with two fresh pages so we can load more content.

Here’s my dilemma: It seems the movieclip unloads itself when the mask enters a new keyframe. I don’t know how to work around this. I’ve tried making a separate movie clip out of the mask, and animating it on its own timeline, but that hasn’t worked. Nothing else reacts this way to a moving mask. Anyonw have any thoughts?

Here’s what I’m talking about:

And the source:
(please forgive the clutter of layers)

And the swf loaded into the movie clip:

Hope I’m communicating this issue clearly enough.
Thanks for any thoughts you may have.