Should be available in a hour or so. After the maintenance. 4:00am UTC
From the US granturismo.com:
The online service of Gran Turismo 5 will undergo maintenance during the following hours:
Start: 09/24/2012 23:00 EDT
Finish: 09/25/2012 00:00 EDT
My guess is that they could have fixed the pop to neutral problem if your shifts weren't exact. Don't have my G27 out right now. Can someone check to see if they made that neutral gap a bit wider?