Has anyone been successful monitoring windows services across different active directory domains with WUP SP1?

This worked great in WUG 8, but I installed WUP on the same server and it no longer works.

Besides opening up port 445 on my firewall (which was required for WUG 8), I've opened up port 135, as documented in the SP1 release notes. I also defined a dcom port on my target machine, and opened that port on the firewall, as well.

I am using a domain admin on the target machine as the account for the service monitor. I even see in my security event log on the target machine that the account is successfully logged into when I test my event monitor in WUP. However, WUP tells me each time that 'The RPC server is unavailable'.

My WUP machine is W2K SP3, and the target machine is W2K SP4.