OpenDirectory.framework: connecting to remote servers?

Question

I'm trying to replicate at least some of the functionality of Workgroup Manager using the NSOpenDirectory.h APIs available in 10.6. I can communicate with my local directory just fine but no matter what I try I can't establish a connection to a remote machine. Here's my ODSession and ODNode setup code.

    NSDictionary *options = [NSDictionary dictionaryWithObjectsAndKeys:@"remote.server.com", @"kODSessionProxyAddress",
@"username", @"kODSessionProxyUsername",
@"password", @"kODSessionProxyPassword", nil];
ODSession *session = [ODSession sessionWithOptions:options error:&error];
NSLog(@"Node names: %@", [session nodeNamesAndReturnError:&error]);
ODNode *node = [ODNode nodeWithSession:session type:kODNodeTypeNetwork error:&error];

Anyone have experience with this framework or know what I'm doing wrong?