Being unable to transfer flavor using a steamer is simply not true. In (NZ) traditional Maori culture we have an earth oven or "Hangi" (pronouned har+ng+ee) where food is loaded into baskets and cooked in a pit where a fire (bonfire) was lit to heat stones. The pit is cleaned after the fire has burnt and the stones put back in. The baskets are put on top of the stones and covered with wet sacking. The sacking is then covered with dirt taken from the original pit. Heat from the stones and the walls of the pit plus steam from the sacking and a small amount of water added to the final mound cook the food. The final product is food that has infused a slight woody, earthy flavor.
Because the process of laying a Hangi is very labor intensive it is usually saved for special occasions such as a wedding, where you are cooking for a lot of people.
So let's try to replicate it in a steamer. While I am going to create a cheats Hangi you can have any combination of vegetable in the steamer. In my case I have whole cabbage leaves on the bottom; one or two leaves overlapping but covering the entire base. Then I have a layer of sliced pumpkin cut about 8mm thick. More cabbage leaf and layer of potato 8mm thick. More cabbage leaf and with thinly sliced carrot 2-3mm and a few more slices of potato. To finish I have some pork on top (de-boned chops) with more carrot added to fill).
That is the general idea it is not a recipe set in stone. Sweet potato is great in there as is brussel sprouts cut in half or sliced. Chicken, lamb or any other meat (or no meat) can be used.
In a 15 cm steamer you can make enough for one or two. In a 20 cm steamer you can make enough for 4-6 people. My measurements below are for the smaller steamer. For a 20 cm steamer go 1.5 times. For larger than 20 cm double it but you will be cooking for 8 or more.
So the real magic begins with what goes in the water. Remember I am trying to achieve an earthy, woody flavor. So I have added to my water 4-6 cloves crushed garlic, 1 tsp Thyme, 1 tsp Rosemary, 1 tsp Sage, 1 tsp Tarragon. You can add others or take some out. In my opinion once you use over four types of herbs the end result gets a bit confusing.
The second key is to have the steamer set low. When you lift the steamer basket or pot you want to be seeing to garlic gently rolling around through convection. Not boiling or even simmering. Low and slow is critical.
The cooking time will vary depending on the size of your steamer and how much you have in it. I expect my little steamer to take about 1.5 - 2 hours. I like to put some potato at the top to test and remember around 8 mm slices. At that size it becomes a good timer. Any bigger and they take longer than the meat needs to cook. After 3 - 4 hrs things will still be okay but the flavor from the garlic and herb mixture will be stronger.