Creating a new drupal field
Create field through the UI
Use the menu to navigate to:Administer -> Content management -> Content types -> manage fields
Also permission must be granted for users to write to the field. Go to:
Administer -> User management -> Permissions
Modify the code
A) To make a field display edit in the drupal UI
Modify the file:sites/all/themes/blackdog/node-ustore.tpl.php
Code extract from node-ustore.tpl.php
B) Add the element to Fedora dublin core
Modify the file:sites/all/modules/ustore/ustore.inc (the function function _dc_content)
Code extract from ustore.inc
I created a function that executes the code above.