Standard Behaviour of Due Date in UWL for SRM Workitems

We have a deployment of Enterprise Portal which is integrated to SAP SRM (7.02). I have two queries regarding the standard behaviour of "Due Date" column in UWL:

1. The column always displays today as the due date for all shopping carts, irrespective of delviery date. I would like to know whether this is an issue and also would be helpful if you elaborate on how is this calculated.

2. The column is showing blank for any workitems other than shopping carts (Purchase Order change workitem, User change approvals, Invoice approvals etc.)

Thanks