My sisters Pom does that! So annoying, I swear if I'm a minute late to letting him in the neighbors must be convinced I'm beating him.
If he's doing it because he needs to go to the bathroom, I would train him to ring a bell to let you know he needs to go. That way he has an alternative means of voicing the problem. When he pitches a fit like that take him over to ring the bell and let him know he needs to do that before you'll do anything. I would also try limiting his water intake in the evening, at 10 months Honey was able to hold it through the night, although 8 hours was the limit, if I mistimed the evening bathroom break I was definetely getting throughly whined at until I got up in the morning.
Another way to break the cycle might be temporarily increasing his bathroom breaks, in addition to teaching the bell; that way his yowling isn't what's catching your attention and bringing you over to him.
You don't want to ignore him when he really has to go of course, but if he's doing it to get food, or just get you to play with him and ignoring the behavior isn't working, I don't know what might. Have you tried teaching him the bark command yet? Once I taught Honey that one, I also taught her speak, as a seperate one, where I treat on soft growls instead.