It should simply work with RSForms (or should do!). Basically, if you have a form field in RSForms that is named email, then the form is validated using RV. If there is no email field, then RV2 will ignore the form (so for any forms you do not wish to be validated, use another name for email).
Let me know if the above doesn't seem to be the case. I did the modification on request, and it works on my test site and for the person that requested it. I can't say it has been exhaustively tested with RSForms, so if there seems to be something missing, just post details and I'll look into it.