There's nothing illegal about driving around with an original certified copy, i.e. a copy that was stamped and signed by an appropriate authority. Just don't make a copy of a certified copy...unless you will have that certified aswell, but it becomes a bit redundant at this point

I have driven around with copiues of my licences for ages, and I have never had any issues with them.
Make a copy of both sides of the card and, if you can, perhaps have a copy of your ID on the same page and have it certified.
People foget that the card itself is just that, a card. It isn't your licence, it is simply a token proving that you are licenced and under what conditions. When you are stopped and asked for your licence, you are simply required to provide proof of your licence, and as for a certified copy, it is as good as the real thing.
For the sake of it, touch base with your local traffic department of cop shop and ask them, but like I said, I haven't had any issues with certified copies of my driver's licence, firearm licences, or ID book.