To add the second E1/T1 interface (assuming that this wasn't configured from the First Time Setup Wizard, follow:
1. Connections > PSTN Connections
2. Add PSTN Connection
3. Choose E1 or T1 and click next
4. Device type should be CUCMBE3000 and Device Internal Gateway - click next
5. Click next to accept the default Cisco Digital Access "Service Provider".
6. Set your preferred Description and protocol type. You can use the advanced settings if you need to.
7. Click finish
Hope that helps,