You could change your Mac OS X system settings so that your default mp3 player is the version of iTunes you want. I did this by clicking on one of my mp3 files while holding the 'control' key, then choosing "Show Info" from the menu that popped up. From the pull-down menu, choose "Open with application". Choose the application you want, then click on "Change All..." and LimeWire should now play the version of iTunes you want.