Where should I put "Do Not Backup" Extended Attribute

Question

Possible Duplicate:
iOS 5.0.1 : How to verify that the folder is marked as “Do not back up” for iCloud?

I'm newbie... I tried to upload iphone application that I created in the App Store and has been rejected. there mentioned that "2.23 Apps must follow the iOS Data Storage Guidelines or they will be rejected". I am confused by the "do not backup" extended attribute.

    #include <sys/xattr.h>
   - (BOOL)addSkipBackupAttributeToItemAtURL:(NSURL *)URL
   {
    const char* filePath = [[URL path] fileSystemRepresentation];

    const char* attrName = "com.apple.MobileBackup";
    u_int8_t attrValue = 1;

    int result = setxattr(filePath, attrName, &attrValue, sizeof(attrValue), 0, 0);
    return result == 0;
   }

where should I put the coding?In the new file or directly inserted in the existing coding? If the new file, what is name and extension of the file? or...???

thanks, sorry, my english is bad..