Also, be aware that IS will by default, send back an xml nicely formatted into an html table, based on the contents you leave in the pipeline. The IS uses a default template. (At least in WM 4.6)
You can create your own template that returns xml based on the contents of a specific record(s). The response goes out based on the contents of the pipeline after the last step within your flow has completed.
#webmethods-Protocol-and-Transport#Integration-Server-and-ESB#webMethods