how to: specify multiple credentials when using svn:externals

I'm new to TeamCity. In fact I haven't even gotten it working yet.

I'm trying it out on an existing project that is stored in svn and uses svn:externals one of which requires a differnet set of credentials.

This project is currently running under cruise control.net and the way I worked around this issue was to run cc.net under a specific user account, then login to svn using that user account to cause the credentials to get cached, and then configuring cc.net to keep the cached credentials.

Is there a way to do this in TeamCity?