Flashpoint FP80 / SRAM S80 - rear hub specifications?
The hub on SRAM S40/60/80 uses a Reynolds freehub.  This freehub body will upgrade it to 11speed.  http://www.jensonusa.com/Reynolds-11-Speed-Freehub-Body/
This freehub comes with new endcaps.  The non drive side is slightly longer and the drive side is slightly shorter.  To avoid having to redish your wheel you may need to use the old caps or just use the the drive side cap side cap

I have heard the Reynold KT 11 speed freehub will also work but I have no personal experience with this.  This freehub is extremely hard to come by in the States, UK has greater availability.