Color tween with actionscript

i think this should be pretty simple but i am new at this stuff.

i have a movieclip named mc. it has a color of
r=255
b=0
g=0
a=70%

i have 3 buttons that when i click i need the moviclip mc to tween to a different color. so when i click button a i want it to tween to the new color:
r=255
b=255
g=0
a=70%

if i click button b it tweens from this new color to a different color:
r=51
b=102
g=204
a=70%

etc. etc.

can someone please help with this?

thanks much