Mantou is a steamed bun. Some people make them with yeast dough, and some people make them with baking powder.
What you're taking about is when we take mantou dough, fry some minced barbecue pork, sugar, hoisin sauce (no idea what this is in english), soy sauce, and green onions (some also use rice wine), then stuff the mixture inside the dough. Well its more like a folding technique, but you get the idea.
This is the recipe I've been using for steamed buns.
3 C. Bread Flour
1 C. Water
1 1/2 Tsp. Active Dry Yeast
3 Tbsp. Sugar
Dissolve the sugar in the water, and proof the ADY in the water. Then mix this with the flour (slowly, as you add more in) There will probably be too much flour to water, but thats why you add it in slowly. Knead and when the dough is nice and smooth and elastic, oil it, cover in plastic wrap and let it rise for two hours.
For the shaping, roll it into a long sausage, and flatten out the ends. Then cut that into 12 different pieces.
While all this is happening you'll want to take a large steamer, and use it to boil some water.
If you want you can put wax paper on the bottom of the buns to keep them from sticking to the steamer (this works wonders, though putting lots of lettuce on the bottom of the steaming racks works too)
When steam is coming out of the closed steamer, put in the buns, they'll probably steam for about 20+ minutes. You should check them after fifteen minutes, if u poke them with chopsticks they should bounce back, but I always let the larger ones (like these) go for 20 minutes, then tear them open to make sure.
I can give u a recipe for "barbecue pork buns" too if you like.