I took a look at google images for his model and the dimmer really is just a dimmer ... providing they sell brushes kits (2) for his model, the principle was ok from the first post; plug it right to the input.
If the person who originally posted the question still follows the discussion; it is strongly suggested that you do NOT use the tool wired that way for too long as the motor will overheat and break (or some of its internals will melt down)... take it as a temporary fix only.