calculation of commission

Hello Guru's

I need to calculate commission in the sales order. It has to come in the sales order automatically. I have done the partner function part and assigned the commission agent to the SP. Now the issue is :

1. What field should i use to create table for automatic pricing. I wanted to use partner funtion type in the table, but am unable to find the same. Partner funtion type is ZL here.

Please advice.

Regards,