If you can play the files with VGMstream, then all you need to do os convert them to WAV, and run the WAV files through a MP3 encoder. Check the readme that came with VGMstream for instructions on how to do this. You will need to know how to use the command prompt, so you might want to search (aka, Google) for instructions on its usage as well. It's quite simple, and people do it all the time. It's one of the reasons VGMstream exists. Hopefully this is a little helpful. I don't have the readme on hand, and I don't have the time to provide in-depth, dwtailed instructions either, but it's really easy, once you know how to use the command prompt. Good luck. Mouser X over and out.
When i am converting the files to wav, there are some info about the file that is being converted. I was thinking that maybe i can use that info to, somehow, encode the files back to the original rsd format.
I just wanted to know if someone has done something similar.