i'm with andrew and chris, there is no easy way, its very much a custom job. what i did, which is no recommendation by any stretch... is cut the side of a datsun1600 pedal box off and weld it to the outside (as opposed to the inside where the stock 1200 one sits) of the 1200 "pedal box". you MUST make sure you get the pedal lined up with the master cylinder. it really doesn't matter a heap which one you use, but i chose one out of a toyota sprinter as they were the best for my size requirements. mount it first then do the pedal.

good luck!