Sales Tax set-up question

I have a tax set up problem with RMS. I am using the "per customer" tax configuration because we ship products out of state and out of country.

Here is the situation: Ontario (local) customers pay GST (federal) and PST (state/provincial) Rest of Canada pay GST only Outside Canada pay no tax

However, in Ontario some products are still non-taxable (which is no problem) and some are GST only (which is a problem).

Is there a way to accommodate all of this?

Also, if I have a customer who is from out of province (with an out of province address in RMS) but who visits my store in Ontario how does RMS know to charge Ontario sales tax? The documentation implies that "counter sales" will be taxed as local sales not as out of province sales but I'm not clear on how this is determined.

Any help is appreciated.

Dan