hey Roadgame
first thing you need to do is take your jersey and flip it inside out. 'pinch' the material that is inside of the back numbers and namebar. can you pull just the jersey material or has the number/namebar been sealed to the jersey? if the cresting has been sealed to the jersey you are likely stuck. the glue on the back of numbers is usually a heat-activated silicone and even if you could get the number off you'd still have a bunch of the adhesive still stuck on the jersey.
i believe josh from north star jerseys is in calgary - he should be able to help you out....
josh@northstarjerseys.com