Fisheye is integrated with JIRA and links issues properly if the issue ID is not surrounded by other characters. Example: XY-123 is linked properly. However, we have been using dashes in front of the issues ids (-xy-123) and that isn't picked up. It is a hassle to go back and revise the SVN log and set a new rule going forward. Is there a way to modify the Fisheye scanner to accommodate for this exception?
There is concept of Linkers that can be configured with different patterns based on what you need:
https://confluence.atlassian.com/fisheye/linkers-298976904.html
UPDATE: In Fisheye documentation stands that Fisheye doesn't recognise JIRA custom issue key formats (Notes section)
https://confluence.atlassian.com/fisheye/linking-fisheye-to-jira-394464293.html
and you shouldn't use Linkers together with JIRA/Fisheye integration. You can try to use custom Linker and check whether the integration still works.