There is very little info on ps3 rapid fire. Its not as easy as the xbox. Hyper made a opensource code for earlier controllers. YOU are welcome to try to port the code over to newer controllers and post your findings.
Nobody has done it, therefore they cannot tell you how, which is why you dont have any responses. Acidmods is not here to do the work for you, we are here to help guide you, your going to have to do all the leg work yourself and post your findings along the way so we may help push you in the right direction.
If you want something I know works, buy the DIY viking ragnarok chip.