Hi there...first time posting, but have been reading for a while. I just saw this note and thought I'd better pop on to let you know what I was told just yesterday.
I saw our Naturopathic Doctor about the plan for our daughter in introducing new foods. She is 5 1/2 months old and is on a lactose free formula; just started rice cereal a couple weeks ago. The ND knows that I drink soy milk as I can't do dairy and she advised not to give our daughter any soy milk or other soy products other than tofu until over the age of two. The tofu will be introduced between 12 and 18 months. She explained that the reason for this is because of the processing the soy goes through; they don't really know what sort of affect it may have on little ones, particularly because soy contains a natural estrogen.
Now...having said all of that, we don't know if our daughter will be okay with dairy or not. If it turns out that she can't drink milk, then maybe the ND will advise to go ahead with the soy milk since she won't have another option. (she had originally advised not to give her soy formula either, but had also stated that if the lactose free one didn't work, then to go ahead and try the soy since the hypoallergenic formulas cost a fortune!)
If you know of a good naturopathic doctor in your area, I'd try checking with them. Or if you have a really good health foods store you could speak to them; they may know what would work. (be careful though...sometimes the people in those stores can be a little fanatical about avoiding things coming from animals!) Alternatively...I wouldn't mind asking my ND for you if she has an alternate recommendation for someone in your situation.