title: JIRA 4.0 - Add "Story Points" field to already existing issues
body: <p>We have migrated to using Greenhopper in our Jira environment.  We have a whole lot of issues where we want to get rid of the "Original Estimate" field, and start using "Story Points".</p>
  
  <p>I have added the "Story Points" to the "Configure Screen" page, however it is only appearing for New issues, the field is not being added to already existing issues.</p>
  
  <p>Does anyone know how to get this field added to already existing issues?</p>
  
  <p>Cheers!
  ben</p>