Paypal calculates wrong cost when a coupon is used

[Belgaron]

Hi,
I am using VM 3.2.2 and latest Joomla version. When I use a voucher the invoice including shipment is calculated right but after forwarding to Paypal a different price is invoiced. Here is an example:

Itemcost: $1.50
Shipment cost : $ 2.00

Coupon value: $3.48

Invoice amount is $0.02 which is correct.

Now I am forwarded to Paypal and Paypal shows $ 2.00 (which is wrong). It seems that the voucher is not applied to the shipment cost for the Paypal payment.

Does anymone have a solution how to fix this?

Thank you.