Add new menu in menu "Supervisor"!!

Hi, All

Can anyone guide or show me how to insert menu in menu “Supervisor”!?!
In my project, wanna do a thing for Supervisor only.
So I wanna create a menu likes menu “Supervisor work area” in menu “Supervisor”
Inside new menu, it’s just for call the customer’s webpage.

I have tried the example customize for create a new menu but nothing happen, look like error in “custom\custom.xml”

Thanks for everyone who will guide or try for me.