There are 3 places you have to put in the 0:
- On the MCD, System Options form, Outgoing External Call Prefix for Applications
- On the MiCollab server, In MiCollab Client Service, PBX node details, Dialing Prefix
- On the MiCollab server, under Users, on each user's list of phones, on each phone's advanced options (so configure this in your templates)