I got an XAct radio for Christmas and noticed the remote appears to be based on the same Kenwood remote. I assume you could use Hijack to remap it to approximate the original remote.
http://www.xactcommunication.com/Visor-29/XRM03-Visor-Remote-Control-108.html
They're $10 on Xact's site.
Oh, you would lose two buttons though...