What do you mean by "register"?
As far as I know, just change your status with the CRA to married and that's it! I'm getting married later this year also in another country, but don't plan on submitting any documents here to anyone. Will keep an english translation of the foreign marriage certificate in case anyone asks.
Well, in some countries you can register with the vital records office, not as a new marriage, but as an existing one. If this was the case here in Canada, in meant we could have a Canadian marriage certificate. I've searched around, and haven't found anything similar here.
I've changed the status with CRA already. They haven't asked for documents yet, but I get this year they might come back and ask, since this year is my first year of filing married. I hope before my husband's visa will be ready before I submit my taxes: I've heard horror stories about the complexities of filing married when one spouse doesn't have either ITN or SIN.