thats a tricky one in these parts of the woods er uh sand....I saw soy milk in Al Meera, so call them and then get the number for Family Food Center and call them too. Although sometimes the people answering have no clue what you are talking about.
Best answer is: try the New LULU hyper next to Landmark. They have a lot of things from America there, like thrity riyal for an american box of cereal... sounds like mega money mart fever is catching on....
good luck