How to include soy milk in bechamel
If the soy is "sweetened", I would not suggest using it in a savory sauce. However, if it is unsweetened, it should be ok. I personally like soy, but it all depends on the brand, and whether full fat, sweetened, plain or vanilla as to how I would use it. You might try baking with it, perhaps muffins, cake or biscuits - and substituting the soy for whatever liquid you would otherwise use.