To elaborate on Ron's question, do you plan to use an OFA/RS remote, or IR-Clone, or a JP1 remote, or some other technique to get discrete codes into your MX-500? Finding the codes you need is only half the work.
If you don't recognize any of these things then you need to do a lot of reading on this forum, on
www.hifi-remote.com, and on
www.irclone.com.