MSProxy, Telnet port and Attachmate’s TC

I just recently installed MSProxy; we use Attachmate’s Intercom to connect to a Unisys A Series. If I install the WinSock Proxy Client (so I can enable POP3 and SMTP), I can no longer reach the A.
According to the configuration of the Attachmate paths it says it uses Telnet port 23 to communicate. I tried opening that port on the Proxy, no go. Attachmate is no help.