var slashIndex = id.indexOf('/');
var serviceName = id.substring(0,slashIndex);
var id = id.substring(slashIndex + 1);
(this.service.serviceName == serviceName ?
this.service : // use the current service if it is the right one
dojox.rpc.services[serviceName])(id)// otherwise call by looking up the service
.addCallback(callback);