STO Scenarion with - Ve cost as custom duty

Hi,

I have created a condition type let say X1,

I am doing a STO scenario, from Plant A100 to Plant A101 in company Code A001

Now requirement is use condition type X1 for values as - ve as well as +ve depending on situation.

I am able to do so, by choosing

Cond. class : A

Calculat.type :A

Cond.category: -- Blank

Plus/minus: -- Blank

Challenge I am not able to book planned Freight Invoice for + Ve Acrual case ,as I am not able to Maintain vendor for that condition type .

Any one having idea to meet the requirement for same condition type with +/- value depending on situation.

Regards

Sunami