onda clone - transparency color
 

I am new on this forum and my native language is not english so please forgive me if will make some mistakes.
I have an onda clone mp4 player and when i saw on this forum how others try to change the look for their players i started to make also a theme of my one.
I have 00.00.0004_2008 firmware and i was able to made with the help of FirmwarePuller sofware a lst file for changing some images.
For example the main menu
http://andrei.erdei.googlepages.com/...full;init:.bmp
the settings menu
http://andrei.erdei.googlepages.com/...full;init:.bmp
and also the usb connection screen
http://andrei.erdei.googlepages.com/...full;init:.bmp
but when i want to change first the music player screen i noticed how awfull it is (photo - sorry for mediocre quality)
http://andrei.erdei.googlepages.com/...full;init:.jpg
The parts from original music player screen is placed over my image.
So my question is this:
is there some color to use for transparent pictures for this kind of firmware?
if there is i will be able to change the color in that parts placed over the background making them invisible.
for now i make a player screen like this
http://andrei.erdei.googlepages.com/...full;init:.bmp
but i don't like it to much.
your help will be appreciated.