When I applied for my merchant account a copy of the completed and stamped form for my trade name registration and a business bank account in the same name were enough for proof of business. Like Cory said different MAP's will have different requirements. I would think if you want to work with Moneris they'll be the ones to define what you need to provide.

You're probably right in not needing a business liscence for your business though unless Moneris will accept anything else as proof of existence you'll need one to work with them. Have you asked them if they'll accept anything else as proof of existence?

I didn't have everything my provider wanted when I first applied, but with a little back and forth they were able to come up with other things they found acceptible.

You can also try other providers that might be fine with the documentation you already have.