Outbound Caller ID on Skype SIP Trunk

I have 5 inbound numbers on a Skype SIP trunk. Went into Skype Manager and set one up as the Caller ID for the trunk, but no matter what I do in FreePBX Admin, it will not allow me to use any of the other numbers as an outgoing Caller ID (ie – if someone is dialing using a certain extension, I need the DID# for that extension to show as the caller id).

Any ideas, or is this a Skype limitation?