Hi,
Did you maintain the VAS step in WC ?
are you going with inbound & outbound sections are different 'or' with total section?
Did you maintain the " /SCWM/TWORKST - Define Master Data Attributes " for WC ?
if all the above is maintained, finally you can check ' Optimize Work Center Determination in Goods Issue'.
below is the path
SCM Extended Warehouse Management-Extended Warehouse Management-Master Data-Work Center-Optimize Work Center Determination in Goods Issue
BR,
C K Reddy