M.N.
The first thing you should try (along with the cutting back of liquids before bed) is to make it routine to go to the bathroom right before he goes to bed and then again first thing in the morning. Make it a habit - even if he says that he doesn't need to go tell him to humor you and to just try. 9 times out of 10 he'll need to go at least a little bit.
Second buy a good waterproof mattress protector if you don't have one already.
Third, pay attention to how wet his diaper is each morning - if he goes a few days with a dry diaper just get rid of the pull-ups all together. If he has a few accidents after that it's OK - he needs to get used to the sensation of peeing at night and having it wake him up. If he doesn't have a diaper on and he pees the bed he won't like the feeling - no one like to sleep in wet underwear or a wet bed - this will help him learn about waking up and the timing needed to get to the bathroom after he doesn't wake up. When he does have an accident get up with him teach him how to clean himself up ( I just put my kid into the bathtub) then stripe the bed with him and show him what needs done with the linens. That may in itself get him to learn what the sensation of peeing at night feels like, but as long as you have pull-ups on him at night he doesn't have to worry about getting up - it's too easy to wake up and say "oh well I've got a diaper on, I've got time"
Also please remember some kids pee the bed at night - for some kids their bladders don't grows as fast as the rest of their bodies - it's just important that when he does pee the bed you show him how to take care of it and that it's OK it happens.
I hope this helps
-M. (mother of 2)