well, you cant do much else but redistribute your weight. Without a low center of gravity, you cannot get up the ramp.
unless, though, you have some weird robot that requires a special routine in order to climb the ramp. in that case i would talk to your programmer to develop that routine.
I wish i could help you more man, but without your robot in my view thats kinda hard to do.
--ss32
(sorry read my next post... i dont think i read your description of the problem clearly enough
)