You should be able to learn the commands from the RM-LJ304 remote on your RM-AV2500T.
After moving the easy scroll key to select the soundfield, pressing the key again sends the command to the receiver, so it should do the same thing if you put the 2500 in learn mode and press the key while pointing the 304 at the 2500.
I'm putting the link to the manual for the RM-LJ304 here in case it is needed.
[Link: 129.33.22.12]