partner functions for sales document item

Hi all,

I wanted to assign a 'sales person' function to a sales order. And it should be MANDATORY.

I did all the config settings in VOPAN, attached it to the sales order type. I also made sure that partner function 'sales person' is made mandatory in all relevant assignments. Still it is not shown in that sales order...

Can u tell me if i m forgetting something? Or watt else can be done to make it mandatory?

Thx. _prashant