If it were me, I would adjust the colors in my Graphics editing program the way I wanted on each frame. I'm not sure what you are doing without seeing. I am new to the DXTheme thing as well, and have found, with a lot of advice and encouragement from people here, that you can do a lot without having to script. If you are animating the entire wall/background as well as the object attatched to it, I may have a suggestion. Depends on what you are doing.
I recently tried an animted wall in my 2 latest DXThemes. I ended up with an ENOURMOUS
21MB file for the theme (22 png's at 1024x768) and the animation wasn't what I envisioned. I ended up solving the problem by NOT animating, but still getting an animated wall.

And I knocked 14MB off the file size of the theme and have background music looping through my non-animated animated object.