Flash lite? Do U mean flash menu?
You must copy flash file (*.swf) into TPA/PRESET/SYSTEM/DESKTOP/FLASH (U can use XS++ to do it)
Next copy theme file (*.thm) to M2 or Phone memory
When you will change theme the main menu should change too ;)
If U can't use XS++, write, I'll try to educate U :D
(You can make own flash menu but it is very difficult.)