10.6 iCal server using 10.5 Open Directory

Has anyone had any experience with getting a 10.6 server's various collaboration services working with a 10.5 Open Directory? I have the web services working fine, but I'm having trouble getting iCal running correctly. First, 10.5 clients trying to connect to the 10.6 iCal server won't work via Kerberos. The other problem, is when I connect via digest mode (or whatever the unsecure mode is), the iCal clients don't seem to get anything back from the server. I can create events and I see them via the web interface, but events created or edited via the web interface don't get pushed back to the client.

Thanks for any help...