My burning project

So this afternoon I get it in my head that it would be cool to have an english version of Phantasy Star Collection, right? So here's what I do:

While exploring the PSC disc, I found that the four games on the CD are simply emulated rom files from the original cartridges. The ROM of Phantasy Star 1 that I have on my computer is the exact same size as the Japanese rom on the CD. The roms for games 2 and 3 are not the same size as the roms on my computer, but I found that I can run the ones on the CD in GENS and Genecyst just fine. Phantasy Star 4 poses a problem - there's no single ROM file that the game runs from. It appears that the game is executed from a library of multiple files. Oh well...

I made an ISO image of the CD. Using WinISO, I was able to delete the Japanese ROMs from the image and replace them with appropriately named English roms. I saved the modified image, burned it to a CD, and popped it into the Saturn....

The CD booted just fine, with its menus and all. Unfortunately, the games themselves didn't work. PS1 didn't boot at all, PS2 did boot, but the graphics were horribly messed up (the music played perfectly, however), and PS3 also failed to do anything spectacular.

Anybody have any suggestions as to why this didn't work??
I'm not the expert on this, but I believe that the rom images used were at least partially "hacked" by sega in order for them to work with whatever they were using to interpret them on the saturn.

In other words, they are not just standard rom images as used by most genesis emulators. I know of no way to "patch" your roms to work with PSC.
the games have a crc protection which you'd need to crack in the first place, but even then it wouldn't work.

the games are NOT emulated fully.. only a small part of the rom is used at all (graphics for example.. which are in different places in the US roms), the rest is ported code, not emulated.

so in other words, no way to do it by replacing the roms.