#1
I'm trying to upload an mp3 but it doesn't allow me to change the kHz. Only the kbps. However when I have a Wav file it allows me to set the kHz.
Gear:

Guitars:
Takamine Gs330S
Fender Standard Stratocaster
Ibanez RG3EXQM1
Epiphone SG G-310

Amps:
Crate Palomino V16

Pedals
Ibanez TS9DX
Line 6 Tonecore Uber Metal
#2
Get an audio converter, convert it to a WAV file, change the kHz. Upload.
Convert it back after if necessary, I suppose. =)