Jorge - the coma corrector distance to the camera sensor must be exact to get the proper effect. I looked up the MPCC mk3 (not sure if this is your version or not) and the distance from the corrector to the sensor must be 55m:
-- camera side connection: M48 and T2
-- Focus distance from the T2 thread: 55 mm
-- Focus distance from the M48 thread: 57,5mm (with the optional Adapter BA2458405 the distance turns to 55mm)
http://www.teleskop-express.de/shop/...-5-to-f-6.html
The off-axis guider takes up 13mm, the Canon takes 44mm (from memory), so that may work but better if you had a dedicated spacer.
You'll then have to make adjustments to your scope to get enough back-focus so that the whole image train can get to focus.
-Cam