Movie clips contents alpha at different rate during Tween class tween

This behavior has driven me crazy in the past.

If i have a clip with a bunch of stuff inside it (on layers) like other clips, bitmaps, etc. and perform a tween on that clip (via tween class), the stuff inside the clip seems to alpha at different rates.

For instance, i have a clip with an empty movieclip which loads a bitmap image and on top of the bitmap image, i have a gradient feathered edge (.png) bitmap and on top of that I have some dynamic text (embedded fonts).

The bitmap is supposed to create a feathered edge on the photo but since they alpha at different rates, you always see the hard edge of the photo…

is there a solution like cacheAsBitmap which would let the whole clip alpha at once? If it’s cacheAsBitmap, i must be using it incorrectly, b/c it’s not working!