How to maintain tax code for MIRO

Hi

I want to add a new tax percentage to the existing tax code VN for MIRO.

I have created a new condition type ZST and added that to the condition procedure. I am using TAXD as the procedure as its an ides system and configured for Germany(DE). i went to FTXP and gave a value for the tax rate for the tax code VN for the condition type ZST. it already had an input tax VST of 16%.

but when i go to MIRO and enable the calculate tax checkbox, it gives the value as 0. i get the correct value wen i remove the 4% that i have given for ZST.

How can i make the system calculate the value for ZST as well for the tax code VN??

Regards,

Sujai