We have a Cisco Unified Call Manager 7.0 and a Siemens Rolm 9751.  Presently we are trunked with seperate PRI T1s and DID numbers specific to each telephone system.  I'd like to consider funnelling all DID calls through the CUCM, however I don't want to change extensions on the Siemens Rolm.  How do you, if you can, forward a DID number through the CUCM over the Rolm?

Example - Today - 7168887800 is a DID going to a PRI on the Siemens Rolm.  7800 is the extension of a phone on the Siemens Rolm.  CUCM will route a call to 7800 via route pattern and a private PRI between the Siemens Rolm and CUCM.

I would like - 7168887800 the DID going to a PRI on the CUCM.  I would like 7800 to remain as an extension on the Siemens Rolm.  How can I get the CUCM to recognize the incoming DID call as valid and route it off the the Siemen's Rom?