There's no way to add new features to the player software. It's totally closed source. (Edit: Okay, the empeg developers could obviously do it, and they do participate quite a lot on this board, but the average user is totally unable to do it, and the empeg guys are busy with other stuff.) However, there is a way to customize the shuffle.

The description of how to set up custom shuffles is here, in the section titled ``Player Config Options in config.ini'' directly under the first table in that section (the paragraph starting ``Custom shuffle modes ...'').