I got some frozen steam buns in Chinatown and tried to cook them. I steamed them in a bamboo steamer (over a wok); one for 15 minutes, the other for 20. I guess they came out done, but in both cases they were wet and gummy. I steamed another one for 15 minutes, then gave it an addiional ten in the toaster oven -- this time it was hard (not dry) but gummy inside. What am I doing wrong? (If I had a microwave, I'd try that, but I don't have one). Any suggestions?