It looks like you are trying to start process instance from kjar/project which is deployed on kie-server, am I correct ? To call external webservice are you using REST service task in your jBPM process?
Are you able to start process using curl utility, like as:
curl -X POST -u 'user:password' -H 'Content-type: application/json' 'http://localhost:8080/kie-server/services/rest/server/containers/soap_tst_mm_1.0.1/processes/soap_tst_mm.call_ws/instances'
I suppose you are right. I developed simple process (1 task calling WS) with web designer. I have managed to deploy it into server, but I could not run it.
Starting process with curl didn't succed - web console returns error 404 - maybe there is no kie-server, for now I'm just using jbpm-console
I'm not using REST Service task - this one works fine, I am using WS Service Task, which is nto working.
As I mentioned before In kie-deployment-descriptor I defined work item Handler new org.jbpm.process.workitem.webservice.WebServiceWorkItemHandler(ksession).