This is a known problem, they are almost impossible to learn. Do a search on this forum as well as the general universal and Pronto forums for more info.

Actually, there have been threads in the Pronto forum where people have discussed how there were able to get the DSP stuff learned, but it's very tricky.

You may have to settle for doing everything BUT the surround stuff on the 15-1994, and keep the Sony remote around just for when you need to adjust the surround.

Rob.
http://www.hifi-remote.com/