Using ShowWebViewCmd

System

I'm trying to create an icommand in Desksite that displays a web view in the Desksite browser window. A bit like the Show Web View comand, but I want to change the standard url that gets passsed to the browser address field in Desksite. I have tried an event handler capturing the imanextlib.showwebviewcmd, but the context items don't seem to have any property that relates to the url and the events don't get captured. Does anyone know if this is even possible ?