Create Mac OS X application that modifies text files owned by root. (Using a privileged SMJobBless helper)

Create a mac application and deliver its source code. The application should feature an window with a text box and a button. Pressing the button will write the given text into a configuration file that is owned by root. Privileges to change the file should be acquired using a SMJobBless helper. The text should be written to the file wrapped with comment lines like this: ####DYNAMIC#START multiline content from text box goes here ####DYNAMIC#END Rules for writing the text info the file. 1) Text file is owned by root. 2) Check if file exists 3) If the file is not empty and there's no text-block with the wrapping comment lines. append the text from text box with the wrapping comment lines to the file. 4) If any text block with the comment lines already exist, replace the entire block. 5) Use SMJobBless helper to have privileges to modify the file. 6) Use Objective-C (and C if needed for the privileged helper) Requirements: Application is targeted to Mac OS X Lion (10.7). Please deliver a XCode 4.2 project, containing the code for the Application and the Helper.