Plug-n-Hack (PnH) is a proposed standard from the Mozilla security team for defining how security tools can interact with browsers in a more useful and usable way. More info about PnH can be found in this blog post.
The interesting thing is that OWTF now supports this standard and below you can find a mini guide on getting things going.
Currently Firefox supports PnH through FxPnH add-on, so you must have it installed( Add-on can be downloaded from here ).
Make sure you have the latest copy of OWTF ;) , start owtf along with --proxy flag.
Fire up your firefox & check the console for PnH configuration link.
Click on the setup link in the console.
You can revert back the proxy settings using this command in gcli (Shift + F2)
pnh config clear