$0 fees throw errors upon being processed; need way to bypass $0 fees

We have been having problems in that we have a variable recurring fee, that is sometimes $0. This creates errors and unnecessary calls to authorize.net. I could find no way to address this without hacking the module. Possible fixes: a) an option to automatically process $0 fees as successful without hitting authorize.net, b) a value in the $fee, such as $fee->succeed that can be set in the existing hook_recurring_renewal_pending , that would be read by uc_recurring_charge_profile to return true without processing, or c) a hook somewhere else, perhaps in uc_recurring_charge_profile, to intervene in the system, perhaps coupled with an $op. This could also be very useful for purposes of debugging.

Here is my hack for this issue:
function uc_recurring_charge_profile(&$fee, &$order = NULL) {
if (!isset($order)) {
$order = uc_recurring_create_renewal_order($fee);
}
if ($fee->fee_amount == 0) { // you could couple this with ' && variable_get('uc_recurring_succeed_0_fees', FALSE) '
return TRUE;
}
return uc_recurring_invoke($fee->fee_handler, 'renew callback', array($order, &$fee));
}