Hershel,
This has been an issue for a long time and part of the problem is that we do not have an easy way to do this. First of all you need to find out if the carrier will accept a code or are they looking for a flag to be set for private calls. If there is a code then they would need to use that code when they call out, but if they are looking for a flag to be set on the setup message then we don't have a way to do that; even though I have asked for it a million times already. You can have it setup on Police Departments, in the US, that if they see a certain outbound Caller ID then they are to block it when sending Caller ID out, but I have never been successful getting carriers to do this for other customers. The only other option that I have been successful with is installing a POTS line on the system that they would direct access that by dialing a "feature code" which has a numbering plan reference to go out that POTS line, remove the "feature code", and insert *67, unless *67 is the "feature code" that you use to do this with; I made that read easier than it is though.
Thanks,
TE