The rb5009 does not do HW offload. The HW would be capable of it, but the limitations are so severe that it will probably never happen. See this post: http://forum.mikrotik.com/t/l3-hw-offload-support-on-rb5009/157163/13
Your route is showing the “HW offload” flag because the route is “unreachable”. (This is a quirk in the interface…)