An important choice is the type of bean used and on this I suggest you order a sack of Laura soybeans from Fairview Farms. http://www.fairviewfarms.com/ Their other soybeans are also top quality for cooking, but these are the nicest for milk-making.

I do not have any relationship with either company, I just admire their products.

Here are a few soymilk tips:
-you can soak a larger amount of soybeans (in the refrigerator for 24 hours in the summer to prevent fermenting), rinse, and store in a ziplock bag in the freezer for convenience. Just take out what you want to use and let them thaw in the water you are going to use to make the soymilk.
-most people like the taste better if you add 3/4 tablespoon of salt and 1-2 tablespoons of maple syrup or other sweetener to the freshly prepared beverage. Only if you are not on a salt-restricted diet, of course.
-for a doubly rich beverage, great for cooking, prepare one batch, leave it in the machine, remove the bean pulp and add fresh beans and then run a second cycle, using the soymilk in place of water. This makes a knockout base for "cream" of mushroom soup or butternut squash soup.

However, let me caution you that if you use soymilk in place of dairy milk, it has almost no calcium, and your diet will need to be checked for calcium and possibly supplemented to prevent osteoporosis. The only two vegan sources of abundant calcium I know of are collard greens and ground, unhulled sesame seeds, and not many people are willing to eat 2-3 cups of cooked collard greens or 3/4 cup tahini every day.... So you may need to consider supplements.

I have not used a vitamix for this. The stainless steel container would allow you to use hot water to rduce the beany flavor, but you would still have to transfer it to a stove and use the cooking instructions to deactivate the soy enzymes that interfere with digesting the proteins in the soy, then strain it. If you dont use much soymilk, it might be OK, but the soymilk machines are quite a bit cheaper and much easier to use for this task.