I've posted this in another thread, but it's really not hard to become a real bedwetter. I did it after maybe 6-7 months with wettings once or twice every two weeks. Now, about 10 months into nightly diaper wearing to bed, I wet probably 4-6 time per week! Be careful what you wish for because from what I can tell, I couldn't stay dry if I wanted to and I never know which 4-6 nights per week I will be wet. It means I have something extra to think about if i go away for a weekend or whatever.
You're doing it wrong. You need to wet in the AM BEFORE you get out of bed, not at night before you go to sleep. When you wake in the morning, empty your bladder before getting out of bed. Do it EVERY SINGLE MORNING. After a few months you'll notice it is easier and easier to do. Eventually you'll be "half asleep" when you do it. Then, suddenly one morning you'll wake up with a wet diaper and think to yourself, "gee, I don't remember wetting this morning". Keep doing the same thing every morning. Before you know it you'll have more and more real bedwetting incidents. Keep at it and you'll become a real bedwetter.
That's how I did it, and I never had a bedwetting problem as a child or any other urinary problems in my life.
You have to form a genuine habit of wetting in the morning while in bed. After a while, the habit becomes the norm and shortly thereafter you'll have no choice in the matter.
Again, you say you're sure you want to sleepwet, but keep in mind that people will eventually find out (that is if you ever want a girlfriend).
If you really want this, follow what i said above and I GUARANTEE you it will work. Just give it time and be patient.