Alright, the fetchmail that come with SuSE 9.0 is actually kerberized... Go figure it wasn't in 8.2 but that's beside the point.
All I had to do to get it working correctly was add this to /etc/services:
kpop 1109/tcp # Pop (kerberos)
Then all I did was restart, and install sendmail in place of postfix. Now it works perfectly! Well bare in mind that I updated to kerberos 1.3.1 and it's subsequent libraries.
Anyway, thank you to anyone who was trying to help!