exhaust for vespa 100 sport

Hi, I have a small problem,

i am building a 100 sport and am having trouble finding a suitable exhaust.

set up;

135 Olympia kit

350 x 10 rear tyre on 2.10 sip rims.

i want to keep the battery box so my problem is that I can't find a exhaust that will clear the tyre, I have machined the swing arm and clutch housing also am going to run a straight rear spring. I don't want to offset the wheel.

Has anyone got this or similar set up?