Dunbarkev,I asked for a raise once. It's pretty awkward.
Only advice I can give is if they won't give it straight away, at least get them to set some measurable targets agreed for when a raise will be given.
Make sure they're documented, as I'm sure it's a management technique to promise the world, and then keep fobbing you off!
If they won't budge at all, the only other way is the classic find another job, hand in your notice, and then they suddenly may realise how valuable you are and be ready to negotiate.
This approach is all or nothing though!