I,m dusting off an old thread here, but I am going through this same problem with a different twist.
I installed the CB radio on my 2009 SERG, and now the bike must be in neutral to start. However, my issue seems to be a self-inflicted wound. Unfortunately, not my first, and probably not the last. I remembered the clutch interlock switch, and I vaguely remembered this thread, which saved me a lot troubleshooting time.
As stated, the CB kit required getting into the left handlebar control housing for the squelch switch. I ordered a lower half chrome control switch only rather than used the black replacement switch in the kit. My tech installed what I requested. I think I got the part numbers off of this site, but it really doesn't matter because I specified the parts to be ordered.
It now works bass-ackwards. It starts fine in neutral. It will not start in gear with the clutch engaged, but it will attempt to start (like prior to 2006) in gear with the clutch out and launch the bike forward!

I'm guessing that the lower left switch unit came with one of the pre-2009 clutch switches. The good news it there is a lot less angst because I know I an start it in neutral and I have a good lead on how to fix it.