Freepbx removing leadin Zero from CID

Hi,

I have just completed an install of freepbx and find that on ALL incoming calls the leading “0” is being removed from the CID. This causing an issue as when people try and dial the phones are remembering the numbers and inserting the full number when people try to dial extensions. EG. we use internal extensions 100-199 so a caller rings in with a number 0123456789 which results in the CID 12345679, as soon as I try and dial any internal extension starting with 12 the rest of the number is inserted.

I tried the instructions here http://www.freepbx.org/support/documentation/howtos/how-to-change-incoming-callerid but that ended up inserting several hundred Zeroes and broke the system.

Any help available would be appreciated.

I do have the SetCallerID module but not 100% sure how to set it correctly?

Regards
Drac