I'm not sure what you are referring to here. Are you adding to the command library, or to the RTI function configuration?

If it's the library and you're using the unofficial, undocumented, unreleased and unsupported (get the drift?) hex editor then the answer is no. You can append new learned codes to a library by adding them with the text editing tool then using the learn tool.

If it's the button configuration, you just add buttons to one of the 12 frames.

DJ