Yeah, an MTP will definitely resolve this issue, and is the "correct" option.Please see: http://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/8_5_1/ccmsys/accm-851-cm/a05mtp.htmlThis should give you a good starting point in configuring your ...
The basics would be to create a new dial peer for the new number block.If you are still using the same provider there will not be much that needs to change as long as the extension (subscriber) block remains consistent with the new number range.ie yo...
Where are your contacts from Outlook coming from? Are they objects in LDAP? Do you have more than one Exchange server?Do you have outlook integration configured, and are you able to search local contacts within Jabber?
Are these registered to the same phone system?Are you able to make external calls to the SPA phones?Are they registered via SIP or SCCP?Is there a firewall between the phones and the phone system?