dispatch different response for external client request

I'm attempting to intercept an external client request and have the mockservice send back a different response accordingly e.g. request name =1 --> response 1, request name 2 = response 2. I can get the request values to be intercepted within the soapui application but *not* from an external client.

I have tried script and query_match. What have I done incorrectly, can't I use the dispatch framework for external clients? the holder["//UserLogin"] is blank for external requests

e.g.

// create XmlHolder for request content
def holder = new com.eviware.soapui.support.XmlHolder( mockRequest.requestContent )

// get arguments
def arg1 = holder["//UserLogin"]
log.info"value is [$arg1]"
log.info"**************************************************************"

if( r == 2 )
   return "false"

//for other values return another response.