What is your connection to the PSTN?
If it is sip, then you want to apply the command on the outbound interface. For example if your SIP trunk account is T01 and your e911 number is 256555444, then apply the following command:
(config)#voice trunk t01 type sip
(config-T01)#caller-id-override emergency-outbound 2565554444
Let me know if you have any other questions.
Yep, it is sip and that is where i placed it. Thanks!