PT,
Yes presuming a T7416. If you have an ICS 2.0 or better just do it from another set, if you don't temporarily replace the T7416 with an M7310 and place the lines on the keys, then switch back. YOu will need DR5 and above for this. The T7406 uses M7310 buttons 1,2,3 and 7,8&9.
If you are using an ATA to analog phone, you program the ATA as a normal phone. Only thing to note is it is only possible to move between two calls.
PhM