What to do with a boss fv300l volume/expression pedal?

[Stephanar]

Hello guys!
A friend of mine gave me this pedal to see if I could find some use for it, but I went into the same problem: it is a low impedance pedal and don't work well with passive instruments without a buffer in front of it. I don't have any pedal with an expression pedal output. Basically, for us, the pedal is a paper weight and too much trouble to sell.
So I started thinking I should build something for him inside of it. But the pedal is very strange, it uses a slider pot to control volume. The value should measure around 10-20k. Will check that later.
I guess my best bet is to find a pedal that uses a pot with this value and use the one inside the pedal.
Any suggestions?

[Stephanar]

Some pics of the big guy. The only parts inside of it are the slider pot (which is in perfect condition), a pot to control minimum volume, and 5 jacks.
Tried to measure the slider pot but I'm not sure where to do it. The only measurement I've got that makes sense is 20k.

[PRR]

> don't work well with passive instruments without a buffer in front

So build a buffer in it.

Tons of room.