I don't have first hand experience with it, but it looks like
this gizmo will let you at least teach an MX-500 the whole set of 950 commands from someone else's remote, and possibly allow some programming from your PC.
An alternative (or supplement) to the MX-500 is a One-for-All remote and JP1 cable (about $40), and download Ellen's 950 remote file which has all the important 950 buttons programmed onto the One for all remote.
[This message has been edited by tofufot (edited February 12, 2003).]