IUPEK Preboot only works with one scanner

I have a Latitude D630 that I can only get the preboot authorization to work with either the internal fingerprint reader or the external reader, not both at the same time.    If I go into Embasy Trust Suite and set up the external one, then unplug/undock and reboot, the internal one will read the fingerprint but then ask for a password anyway (and vice versa, set up internal one, and the external one won't work).    I've got 3 other laptops using both the internal and external readers daily with no problems (1-D620 and 2-D630's).   What's up with this one?!