I haven't used Windows 8, but the latest broadcom driver for the M4600 / M6600 works with under windows 7 using either microsoft windows biometric framework or dell data protection. I have been using dell data protection, but WBF works fine so I will probably just use it. I would think that Windows 8 windows biometric framework would eliminate the need for dell data protection. All you have to do under windows 7 is start up the broadcom application and either enable or disable windows biometric framework and then use whichever method you choose.
This page contains the driver installation download for Broadcom USH in supported models (Latitude E6410) that are running a supported operating system.