Sony Ericsson P990i: Vibrating Alert
I normally set my phone with sound and vibrating alert together.
Tools > Control Panel > Sounds & alerts > Vibrating alerts > Message: on

And I remember that the vibrating alert will continue to vibrate along with the message tone. It seem that after I upgraded the latest firmware (Update_Service_Setup-2.7.4.8-2), the message tone will continue to buzz but the vibrating alert could only vibrate once.
