ok, i just needed a good night's sleep to get my head around the RawkSD incompatibility problems. I have found out how to get the missing songs to appear in RawkSD 2 now, which in turn will allow them to be added to your RB2 save game, so for anyone missing songs (affected songs are listed at the bottom of the post), go into the SDPC\rawk\rb2\customs\songtitle folder and open the data file in a hex editor
scroll down to the bottom and look for a section like this:
This tuning offset part stops it from being listed in RawkSD 2 so you need to remove it (i do not know how this will affect the song, but most songs do not have it) you must make sure you remove from the 05 before "tuning_offset" to just before the 05 before "context"
DON'T edit the SDPC\rawk\rb2\customs data file which has all the individual data files combined in it, as this is the one RawkSD 3 uses and if you edit those songs then they will disappear from RawkSD 3 the next time you load it
Affected Songs (list will be updated as i import more songs)
AC/DC Rock Band: None
Rock Band 1: Black Hole Sun, Don't Look Back In Anger, Nightmare & Roam
Green Day Rock Band: Basket Case, Brain Stew/Jaded, Burnout, F.O.D, Having A Blast, Nice Guys Finish Last, Sassafras Roots & Warning
Lego Rock Band: Every Little Thing She Does Is Magic, Ride A White Swan, Two Princes & We Will Rock You