ISA Server in Front of EXCHANGE 5.5

Can’t successfully publish my Exchange server. From INSIDE my network I can telnet to 10.1.1.5 port 25 and get a successful connection. From the ISA server I can also telnet to 10.1.1.5 25 successfully. But when I Telnet from outside the ISA server I cannot connect. Is there a log on the ISA server that shows redirected traffic? It seems the Outer Network Card is not sending the request through to the Internal address. Any ideas? I used the ‘secure mail server’ wizard to create the protocol rules.