Using the RUNAS Command for SMS MSC Across Domains

[BBKCSC]

I want to run the RUNAS command to start the SMS MSC on a server on one domain, pass credentials in a script, and have the Admin Console connect to a site database on another domain across a firewall. I have MMC 3.0 loaded on the first server. How do I do this? I've been able to accomplish this same goal with the Active Directory Users and Computers "DSA" MSC. The necessary ports are open across the firewalls. But I get the message over and over, "The Site database server could not be contacted." The login credentials I'm trying to pass are valid for the second domain. I'm told that the SMS MSC cannot be started like this; i.e. the user has to be logged into the server on the domain where the MSC is started. I hope this is not true.