Ultimately, the extra ports will be "above 32000". It can only be configured via registry but you don't want to do that. If you have multiple servers, all of the ports the client connects with (there are two "high ports") must go to the same machine. I'm not sure what Nortel calls it, but something like "source route routing" set on the LB will cause additional ports from the same client IP address to be routed to the same server, which is what you need.
RTSPS is another option, which causes the client to only use one port, but limits scalability.
