Element Domain Specialization Step 2: Declare The Domain Element Types
Step 2-2. Declare Element Type Name Parameter Entities

Step 2-1. Create New .mod File

Create a new file named "xmlDomain.mod" and put a descriptive header comment at the top: 
<!-- ====================================================
     XML Construct Domain Module
    
     Author: your name here

     Copyright (c) 2011 copyright holder
     
     license to use or not use or whatever
          
     ==================================================== -->