Paypal Standard OC v. 1.3.4 Shipping tax

Hi,
I am testing Paypal Standard with OC v. 1.3.4 (Itemized Patch included and flatrate shipping is set) and everything works fine except the tax on Shipping. When testing it with 1 Product then Paypal shows the shipping without tax. When testing with 2 or more products then Paypal shows shipping with tax. Actually that is how it is supposed to be.
I looked in the source code on guest checkout confirm and noticed that shipping_1 is the shipping fee without tax and shipping_2 is only the shipping tax.

I have included Screenshots and maybe somebody can help me to solve this problem.
Thanks.
beachi