workUnitBForm from outside of a flow?

Sorry for the cross post - its kind of cross topic. I'm trying to provide a way to update workunit and task info from a design studio form. I can get workUnitBForm (and others) to work fine from a web run. However, per the KB article, I should be able to call it directly as a URL call. But when I call it from the full URL outside of a flow I'm getting the message "The DisplayExec" you have specified cannot be found.

Has anyone ever called any of the WF forms from outside of a flow?

This is the URL I am attempting:

/bpm/xml/workUnitBForm.do&metho...;WAIT=true