I think I solved my own problem after all....
I was using:
setspn.exe –A HTTP/server1:1234 SUB\sa-ca
setspn.exe –A HTTP/server1.sub.domain.com:1234 SUB\sa-ca
But in stead I had te use
setspn.exe –A HTTP/server1:1234.sub.domain.com SUB\sa-ca
it is strange because Microsoft didn't mention that in the Kerberos for Moss Instructions and for the SQL server I placed the port numer at the end and that works...