[plesneski]

Would be nice to see it in the core, especially if someone paid to have it put there. For now, this is our solution in the 4.0.x branch:

Somewhere around line 1500 of include/func.php, at the top of function func_calculate_taxes(), find this code:

        $taxes = array();
        $taxes["total"] = 0;
        $taxes["shipping"] = 0;
                           
        $__taxes = array();              
                                                
        foreach($products as $k=>$product) {

And so forth.... Now, after it sets the shipping taxes to zero and BEFORE the foreach loop starts, add this:

        // dealer-wholesalers don't pay taxes
        //
        if (is_wholesale_membership($customer_info['membership']))
        {
                return $taxes;
        }                

Um, we have a custom-built solution for assigning membership levels as "wholesale levels", which is what that is_wholesale_membership() function is, but you can replace that line with the following if you just have one membership level you want to hard-code as the tax-exempt wholesale membership:

        if ($customer_info['membership'] == 'Wholesale')

Change "Wholesale" to whatever your membership level is called.

Cheers,

Paul