I have a call centre customer who has just migrated from ISDN to SIP (with the same carrier).

This carrier on their sip service send 9 digits for the CLI (we have a 2 digit area code (0x) and 8 digit numbers).

I'm looking for a way to add a 0 into the cli that is displayed on the customers handsets, as they use this to bring up the customers account quicker then waiting for the caller to say who they are, etc