I have got my own bundle that I insert into login window. When login window is started up the bundle writes necessary parametr into file which is situated in /Library/Preferences/.My bundle works in login window under user account securityagent. What is another way to write into file?
See: http://www.cocoabuilder.com/archive/message/cocoa/2008/12/15/225471
See: http://www.cocoabuilder.com/archive/message/cocoa/2008/12/15/225471