If it was only that easy.
if i am not mistaken, You had to capture units in battle in the online campain to get new ones. as you won them it was written to your profile. Almost like an achivement.
Once the capcom's campain server went down, you just had to connect to live and they all unlocked.
There is a hack if you have a modded xbox. I only have one old modded left and a pile of 8 differnt un modded limited editions that 1 was trying to avoid modding .
thats ok. Saves me from paying Microsoft for a new live account that i might or might not use... altho i still have a bunch of free 1 month trials..