For configuring cachebox, all settings are gathered under Misc - Settings
GPS    Map    Data-Maintenance    Data-Mail    Misc-Misc1    Misc-Misc2

Bild "misc-settings-gps.jpg" - GPS
To use internal GPS, use "Windows", for external GPS
use "NMEA" to be able to choose a certain COM-Port.
To connect an external GPS via bluetooth take a look here.

Here you can also start/stop GPS
or scan for available GPS devices.

"Use CellId for initial location" lets Cachebox
find a position even without GPS signal
from connected GSM-Antennas.

Use Htc Compass"    No idea!