Need help finding a treble pot for Soundgear 506...has Bartolini Mk-1 System

I tried looking on Ibanez's site and all they had listed under replacement parts was the whole Mk-1 system. Does anyone know where I can get one of these pots? My friend who worked on fixing some wiring issues with the bass says he doesn't know where to find a pot similiar to it (with a notch for where the knob would be on the flat treble eq position). Bartolini's site wasn't much help either.

Thanks a lot in advance for any help!