Connecting to Exchange from Outlook; RPC

I have installed Small Business Server 2000 on a server that I have colocated in a hosting facility. The facility routers block port 135. So I setup VPN connectivity from my workstation but still can’t get Outlook to connect to Exchange. I have no problems connecting with POP, IMAP, or OWA so I know the server is working and my account is active. I wouldn’t think 135 would be blocked once I’ve created a VPN connection but I can’t even setup a profile and have the name checked. It always says the Exchange server is unavailable. I’d really appreciate any thoughts or suggestions.
Thanks!
Jim Kuhr