I have been messing around with my phone for a "shortcut" to lock the phone and can't find anything. I even checked the owner's manual and the only steps to lock the phone are the ones I already posted....SORRY
To lock the phone:
From the main screen, touch MENU.
Touch Settings & Tools.
Touch Phone Settings.
Touch Security.
Enter the Phone Lock Code (the default code is the last 4 digits of the cell phone number) then touch DONE.
Touch Phone Lock Setting.
To lock the device immediately, touch Lock Phone Now.
Touch the preferred option:
Unlocked
On Power Up