now I got it!
I installed the Support Tools from Windows 2003 Server and then I had ksetup, after adding the other domain, I was able to mount a share from the Mac OS X Server with a Win2003 Kerberos Ticket!
But its not working in the other directory, if I have a kerberos ticket from the OS X Server I cannot mount a SMB Share from the Windows Server:
ahu:~$ smbclient -k –user ahu \\\\win2003\\\wmpub
ads_krb5_mk_req: krb5_get_credentials failed for win2003$@WIN2003.EXAMPLE.COM (Decrypt integrity check failed)
cli_session_setup_kerberos: spnego_gen_negTokenTarg failed: Decrypt integrity check failed
session setup failed: SUCCESS – 0
Any ideas, whats missing?