Huru Helpdesk is a Joomla! 1.5 native helpdesk application with built-in knowledge base. It has many features, but I guess one necessary feature is missing.
When Rep is viewing all open problems using Huru Helpdesk control panel, table with problems does not show problems that require a reply. It is hard to decide which problem was replied and which not. Therefore, I had a try to fix it.