It is my understanding that the phone initiates a handshake with the CUCM so it will only obey SCCP messages from CUCM.  Then what about those customer who want to run Secure Skinny?

If you have achieved something like this, I would love to see it.

Hi

Yeah, sounds very tricky.

If it's a requirement, I would look at getting a proper dial-in meeting solution such as MeetingPlace or MP Express. You'd then be able to initiate a conference by configuring a permanent meeting on a known meeting ID, dialing the MP solution, then pulsing out the digits.

I've no idea what you're planning to use the conference for, but you'd have to think it through carefully - if there's any requirement to have multiple callers thrown into multiple conferences then it come become tricky to manage.

Regards

Aaron