Hi
This has taken me a loooooong time to find. I was tearing my hair out looking for a bug in my code, when it was here all along.
I have been using hook_cart_item to change $item->price. The changes I was making were having no effect. It took me ages to find out that it was to do with having permissions to display price without vat permission checked.
The bug is line 113, change:
<?php
$item->price = $product->sell_price;
?>to
<?php
$item->price = $item->price;
?>This made it work perfectly for me.
Glann