You can uncab and makecab using XPander by XPero and simply add it to your i386 folder overwriting the old one BTW making a full replacement addon is simple just paste this into notepad and fill out the fields Save it as Entries_AnythingYouWant.ini and Rar, Zip, 7zip or Cab the Entries*.ini file along with the files you added to the i386 compress section like msgina.dll The i386 compress tells nLite or the Integrator to Cab the file and put it into the i386 folder of your XP or 2k3 CD Source, here is an Example AddOn: Ricks_DarksideShutdown_AddOn.rar