updating nav gear n910?

I have just purchased a sat nav n910 from e-bay and it seems to work fine except that there does not seem to be any way to get new data i.e voices onto it ?.The TomTom home recognizes it and shows all the software folders on board but when i try to add to the unit they do not show up on the satnav screen at all only the preset items are available ,the unit runs on windows CE please help if possible?!.