We are using v4.
I found the problem though. I looked to see that the SupportService.asmx file was in the right directory and noticed that it was, but that for some reason it was excluded (was renamed SupportService.asmx.exclude).
This must have happened when I opened the support site in Visual Studio 2008 as part of the migration process.
Anyway. I droppped the .exclude extension and viola!
Thanks for the pointer.