Suzanne,
Not that I have any idea what I'm talking about.........but would soy sauce work instead of vinegar? Or some dry white wine, like a sherry? And, we MT Protein types are supposed to use vinegar sparingly, right? Well, the food police won't haul us away if we use it now and then, will they? I'm doing great on this MT diet and have used vinegar several times. I've not seen where it has hurt me.