Authorize.net doesn't charge card unless...

I found a solution for a problem I've had.

I'm using the uc_authorizenet module that comes with ubercart inconjunction with uc_optional_checkout_review.

On submission of cart/checkout page the "uc_authorizenet_charge" function wasn't be called from uc_credit_uc_order and just redirecting to complete page; however, uc_authorizenet_charge would be called if you enter in some wrong credit card details first. Then when you corrected the data it would all work.

The problem I found to the problem was in uc_optional_checkout_review_uc_cart_checkout_form_submit().
The line causing the problem was "$order = uc_order_load($_SESSION['cart_order']);"
This was sending over the $order without $order->payment_method being set.
My guess is that the order in $_SESSION wasn't updated yet from the form submission yet like it would be if you went to the review page.

The solution was to replace "$order = uc_order_load($_SESSION['cart_order']);" with "$order = $form_state['build_info']['args'][0];"
This way the $order object was the object that was modified right before from the checkout_form_submit function, which had the right fields set. Everything worked after that.

I also needed a line earlier not to get an error that someone else has posted...
if (module_exists('uc_credit') && isset($_SESSION['sescrd'])) {
$_POST['sescrd'] = base64_encode($_SESSION['sescrd']);
}

I hope this helps someone else.