Order data missing in API to payment portal when using custom fields

[t68]

Hi!
I have run into problem since Payson changed their payment module. They are now using more of the parameters for products, tax etc that VM sends when redirecting to the payment portal. When single and basic products with just one price is in the order it works fine. Looks good in Payson where products, shipping and tax is listed.
But if a product whith custom fields that are cart variants, for example an addon feature or size, are in the order payson doesn´t open.
In their API log I can se that if a product have custom fields some things are missing in the string that VM sends to Payson. These are ".unitPrice=" and ".taxPercentage=" for the items and also ".taxPercentage" for shipping.
Products that doesn´t have custom fields have these parameters sent in the string.

Payson does some calculation on it´s own and if item price and tax is missing it fails and will not open the payment function.
Don´t know if this is a bug. But in the VM cart tax and stuff is calculated ok on the products with custom fields so VM does the math. It just seems to omit these data in what´s transmitted to the payment operators.

If I have missed something in the VM setup, please tell me.
Running VM2.6.6 and J2.5.22