This would allow a custom message composer to generate and format a custom error response. Right now, throwing a WAE from a composer ends up with a wrapped exception which always has a default return code (500) and message (server error).
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira