Create second Business Partner field on Issue Overview screen

Hi

I am creating a new Issue Type for SAP QIM

I am using FPM to add custom fields to the Issue Overview screen.

I want two fields - both to be for a person name - thus have a Business Partner dropdown (like Responsible person)

I have created a new text field,but cannot figure out to make it 'of type business partner'..... i.e. when you click on drop down, you must get Business Partner option.

Any ideas?

Much appreciated

Regards

Marieta