In a server code event you call the web service just like you would from any .NET code.  Declare an instance of the service, set it's credentials and url (if needed), then invoke methods on it.

 InvoiceService.Service1 Serv = new InvoiceService.Service1();
 Serv.Credentials = System.Net.CredentialCache.DefaultCredentials;  //if needed

 //Serv.url =  ...set url if needed
 int ID = (int) K2.ProcessInstance.DataFields["id"].Value;

 bool bl = Serv.DealProfessionalRequired(ID);

---

The statements and opinions made in my postings are my own, and do not reflect the opinions of SourceCode Technology Holdings, Inc. or its subsidiaries. All information is provided as is with no warranties, express or implied, and grants no rights or licenses.