As previously reported, this is not possible with the SDK.
If you are working in a jailbroken environment, the icons on the status bar should be placed in /System/Library/CoreServices/SpringBoard.app with two versions: Default_NAME.png and FSO_NAME.png. The default value is used in a line of a line as a line in the form of a line, in FSO on the main screen or in applications that use a black status bar.
SBStatusBarController has an addStatusBarItem: method, just call it with @ "NAME" as your argument and it will handle the rest for you.
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