Using arcpy to open Script tool

Is it possible to use the pythonaddins.GPToolDialog(X,Y) as part of my python addins toolbar script to open a script tool I have stored in a custom toolbox? Where X is a string representing the location of my toolbox and Y is the name of my script tool. I can use this to open geoprocessing tools but have not been able to figure out how to open my script in the toolbox.

Thanks for any ideas you may have.