Hugs to you mama. That is rough.
I don't know if this will work for you but when I run into these kind of issues I usually just really talk about it with DD or DS. I explain that he/she is tired and that sleep fixes tired... we need to sleep so that we can feel better and have more energyt to play and not be cranky.
I just talk about it all day and we work out a plan. I am a huge believer in the power of suggestion. I used Chamomile but you could use warm milk. I explain that if he/she wakes up in the night, then I will give them the magic tea or milk that will allow them to go right back to sleep! And then they will feel so much better the next day, etc etc.
Then when they wake up I don't let them get up, I just rub their back and sing or just say "sssshhhhh" until they are drowsy or sleeping again.
Also just a random idea... I know this works for night terrors but maybe it will work for this too... If you disrupt their sleep cycle an hour or so before they usually wake up (or have a night terror) then they might not wake up at the usual time. You could try it before you go to bed - just rouse him a little bit. Don't wake him up completely just enough to disrupt the cycle. It's worth a try maybe.
Good luck and let us know what works for you!
Wife to French hubby (8/02), Mama to DD (3/05) and DS (02/07).