There are two restrictions to keep in mind. First, if you're using analog lines, then it can only pass the caller ID of the analog line outward to the cell phone. Secondly, we ran into an issue with EC500 on our Definity (similar feature to follow me) using a PRI where when we would have the system call our cell phones, it would show our main outbound caller ID instead of the caller ID of the person calling. We found the problem was the LEC was not allowing us to send any caller ID, but only the caller ID of a valid DID on our PRI circuit.
Aside from those two issues, I'm not sure if there's something on the IP Office side, but just thought I'd give you a heads up on what I've run into in the past.