Default Custom Vendor

We have a scenario like,

At the time of import purchase order creation we maintain condition for custom duty.

In the first step we have to pay custom duty, for that we have created a vendor called “PNB Custom Duty” and that vendor has to maintain in the condition type at line item level in PO. We want to do default value (Vendor) while appear custom condition at the time of PO creation.

Kindly suggest.

With regards

Rajesh