slowly I despair of how to access TM1 10.1 through Cognos Connection Poral 10.2

Situation: Cognos Connection Portal 10.2 is installed in the DMZ on our webserver and accessible from outside via a https-link. Locally inside our secured network we're operating all kind of BI report servers and also Cognos TM1 10.1.
Problem: The internal TM1 application (//cog-tm1/tm1web -> internally accessible http://cog-tm1/tm1web) cannot be accessed through the connection portal from outside as the internal link is still be used "clear-type" (in a kind of iFrame). So far I thought using the connection portal and the TM1 portlets exactly allow me to access these kind of internal content from outside through the connection portal.
Question: Am I totally wrong with my thoughts by accessing an LAN-internal TM1 application from outside by using the connection portal or do I just miss something?
Thanks a lot for your support,
kind regards
Thorsten