I have the original remote.
I did a web search of the unit online and I found anther remote control site hifi-remote.com. they showed for the minidisc that the keyboard commands were device# 26.97.
[Link: hifi-remote.com]The site shows it as device #15. According to their instuctions you would use the sony12.idr for all device codes less than 32. I changed the device code in the idr file and makehex.exe.
I then wanted to compare the codes from makehex to a pronto CCF that is posted that has the discrete codes. I copied the hex code for one letter from the makehex output to notepad. I went into the ccf file, in prontoedit. Double clicked on the corresponding button on the panel. then double clicked on the learned IR command and then pasted that into notepad. However, the code isn't the same.