I guess Ultima unpack/decrypt the game data relating to starforce and thus need a homemade installer to install it. Either that or they may even just make a dump to DVD of the installed and cracked game and make an installer rather than release the full original game plus an extra load of extra cracked/decrypted data you have to manually install which may make the release even bigger!
Remember how Dead To Rights had to have an extra CD just for the crack! If Ultima had released it it would probably still be on 3 CD's not 4
