I am a legal guardian of my nephew, recently we moved to Canada, I'm on an open work permit and I can not register him into the public school because they do not accept the Mexican notarial letter where it states that I am his legal guardian. They ask me for a Canadian document that proves that I am his legal guardian. But as I am not a permanent resident, in the family courts did not want to give me support. Is there something I can do to get an official letter/paper valid in Canada?