vRA 6.2 - Approval policy, determin approvers from request -> external field empty?

Hi,

I want to create a new policy, where a user who request the catalog item (an ASD workflow) would need an approval from the business manager (or owner) of the element, on which the workflow is running (a vm in another business group as the request user). AFAIK I can determine the approver by using a vRO action, which I would select while creating a new policy, under Who are the approvers -> determine from request -> external. The fiels is empty though:

Any ideas how I could fill the field?

Thanks!