Sending out your your own number, even to a VoIP provider will all depend on whether or not your provider allows it. Because of the possible abuse, spoofing of numbers, possible illegal activity,prank calls, a lot are reluctant to send out anything but the number(s) that you have registered against your account. About the only way to guarantee the callers number forwarded through is to use the call forward feature of your phone company on that line. I know it can be done from a PRI PBX over at T1.