Hiya, think you will be needing an A+P to be working in canada in a certifying capacity, as I understand it the FAA will not give any exemptions for a CAA licence. You will have to go through the whole FAA process. If you want to do this from the UK you will have to prove to the FAA rep you need an A+P to work, ie working on US registered A/C. Hope this helps and sorry if it sounds a little negative, dont think you will find the A+P to hard though.