Step forward the free third-party app ‘Illumination Bar Notification’. The app works for the Xperia P, Xperia S and Xperia U and will light the transparent bar when you have a missed call or receive a SMS text message.
The settings allow you to illuminate the bar with different blinking speeds or keep it lit constantly. The light will stay active until the text message has been read or the missed call has been acknowledged. It can also be set to turn off once the screen is unlocked.
The Xperia U gets most customisation allowing you to choose different notification colours such as blue, red, green and yellow. For the Xperia P and Xperia S you are obviously only limited to the white light. All of this makes us wonder, if a third-party developer could do this, why didn’t Sony include this as a feature from the start?