Welcome to hadit, I'm sorry that you are just starting the C&P process, sad but true that the info hasn't been given freely. (Thank God for Tbird, and Hadit!!!) Anyway, just a little suggestion...if you haven't already, I'd suggest filing for Individual Unemployability! It is listed as TDIU and rated at 100%.
About recovering anything before 2005, I don't think so....but lots of smart people here will be able to tell you for sure. I just know that the date you file, is the date you get back pay to....after winning your claim.
Good luck, you deserve the very best...you have earned it!!! Thanks for your service!
Hugs,
Gwen