There is at least one IFBB pro bodybuilder who is a vegan and has relied upon soy protein for his physique.
I would offer him as an example that soy protein is not a "waste of time." It may not offer the same benefits of whey, I think the scare of its "estrogenic" isoflavones is a bit hyped ... but use it. Just dont make it your only source unless you are a true vegetarian too.
Also, maybe isopure can help you. I hear is lactose FREE.
NFG