Hi,
using VAS like Virendra and Suraj suggest is one way, but requires the pack spec and the VAS step.
Without EWM your requirement is actually quite simple, as in ERP you can create automatically an item for a packaging material. As you can see in note 898987 this does not work with EWM, according some other notes in only works with certain settings.
With EWM 9.1 this functionallity is directyl in EWM: Quote: " As of SAP Extended Warehouse Management (SAP EWM) 9.1, you can configure the system to automatically generate packaging items based on handling unit (HU) information during delivery processing in a goods issue (GI) process."
For details see the release notes for 9.1, the link is here: http://help.sap.com/ewm91
Brgds
Juergen