I'm currently downloading the Steam version.
According to an earlier post in this thread you can use the no-cd fix and then the trainers are supposed to work.
So first thing is to check this out (if it works then no need for a new trainer).
I've tried this, and it just ends up crashing my computer.
*edit* I found out that it was actually my sound card crashing my computer, Creative has buggy POS drivers for Windows 7 */edit*
*edit2* It may of not been my sound card after all, apparently Just Cause can't run on multi-core CPU's so you have to set it to run off of one core or it will crash you */edit2*
[Edited by Predreus, 3/14/2010 4:55:26 AM]