Anything in the administrator is able to be invoked, you just need to dig through the DSP to find the %invoke wm.something.something:serviceName% and work out what it takes in.
So go to the admin page that you usually go to to enable the listener, look at where the link or form submits to and then load up that .dsp page in a text editor. Find the %invoke …% part that looks promising (the names generally make sense). Look at the link that goes to the page and see what the parameters are (they’ll be something like ?param1=something¶m2=somethingElse )
Then create a wrapper service that calls that service by adding debugLog or something and then changing the service that it invokes in the properties by pasting in your “discovered” service name. Then add inputs that match the ones it takes in as the inputs to the service.
Note: your code could be broken by any upgrades/patches put out by webmethods, so you’ll have to make sure things work before applying any patches/fixes/service packs to production.
good luck with it,
WmUnit - The webMethods testing framework