​ABSL里怎么调用第三方的web service

/*
	Add your SAP Business ByDesign scripting language implementation for:
		Business Object: CustomerQuote
		Node: Root
		Action: triggerOutboundDeliveru 
		
	Note: 
	  - To access the elements of the business object node, 
	    use path expressions, for example, this.<element name>. 
	  - To use code completion, press CTRL+J. 
	   
*/
import ABSL;
if( this.OutboundDeliveryID.IsInitial() == false){
    raise already_delivered.Create("E");
	return;
}
var HttpMethod = "GET";
var HttpResource = "";                            // not required
var ContentType = "";                             // not required
var Body = "";                                    // not required
var HeaderParameter : collectionof NameAndValue;  // not required
var URLParameter    : collectionof NameAndValue;
var URLParameterEntry : NameAndValue;
URLParameterEntry.Name  = "SoID";
URLParameterEntry.Value = this.ID.content;
URLParameter.Add(URLParameterEntry);
var response = WebServiceUtilities.ExecuteRESTService("JerryExternalService", "JerryExternal", HttpMethod, HttpResource,
URLParameter, HeaderParameter,ContentType, Body);
this.OutboundDeliveryID = response.Content;
raise delivery_message.Create("S", this.OutboundDeliveryID);