I found the excellent PC savegame guide on stella's website http://tombraiders.net/stella/savegame/TRAsaves.html but I didn't find one for the PS2. After messing around a bit it seems like the PS2 stores "rewards" in a separate file from the actual gamesave so the unlock file can be applied without affecting a game in progress. To manipulate PS2 gamesaves the preferred tool is uLaunchELF. PS2 users unfamiliar with homebrew, or how to run unsigned code can ignore this post altogether.

I have attached the same "rewards" file under two names: BESLES-54674c28_1 (the european save) and BASLUS-21555c28_1 (the american save). These names correspond to the actual save folder stored on a PS2 memory card. Simply extract the files to a USB stick then transfer them to the appropriate folder on your memory card. I always recommend backing up the original data before doing something like this. If this has already been covered somewhere else then please delete this post.

PS2_TRA.zip

How can I transfer this file onto my PS3 memory? The USB stick doesn't work in that case...