i need to call soap web service that get the shipment weight and display it on shipment screen

Summary:

Hello,i need to call soap web service that get the shipment weight and display it on shipment screen

with custom action that fire custom agent to call web service from external system

Content :

here is the error I get in the log (null pointer exception)

here is my agent screen

here is the action tab of the agent in second picture

here is the external system setting

and here is the wsdl doc

note: iam using soap api similar just for trying

Version (Otm 24A):