Command line switch for GoToMeeting to join a meeting by ID?

Question

My colleagues and I have a recurring weekly meeting set up. I'd like to set up a shortcut to that meeting (in Windows 7). I can make a URL shortcut like this

https://www2.gotomeeting.com/join/123456789 

but that fires up a browser window which then has to be closed - it would be cleaner to just call g2mstart.exe with a command line argument to join meeting 123456789. I've tried guessing at the syntax to join a specific meeting but haven't found it, and haven't found a guide to command-line switches anywhere online. Clearly g2mstart.exe takes arguments - the standard shortcut looks like this:

"C:\Program Files (x86)\Citrix\GoToMeeting\457\g2mstart.exe" 
"/Action Host" "/Trigger Shortcut" "/Product G2M" 

Is there a guide somewhere to these switches? And is there one that allows joining a specific meeting by ID?

Answer 1

I found it after a little more trial and error:

"C:\Program Files (x86)\Citrix\GoToMeeting\457\g2mstart.exe" 
"/Action Join" "/MeetingID 123456789"

Answer 2

I guess you will still have to register (the same way as you would have if you used Join... from menu)

I tried and this works flawlessly: "/UserID 123456789"

Would love to find how this could've been done on a MAC