I just stumbled over this document: micro-modular.com/docs/AddlRsrc/GSD4e OSP Manual (CS-129291-DC-9).pdf
So, for example on site 119 for example you can see that it is possible to disable the static navigation filter by sending the corresponding Payload Sequence to the SirfIV chipset. The only question which remains is "how can we send these strings to the chipset".
And this is the point where we need some really brilliant XDA developers. If someone would manage to open the communication way to the sirf IV chipset, it would be possible to reconfigure this chipset totaly free.
At the beginning it can be a really simple tool where you have to enter the Start sequence, payload and end sequence which should be send manually. This would be good enough. But the biggest part will be to find a way to communicate with the GPS chipset. Maybe someone knows some good tools to find out how to communicate with the GPS chipset.
I'm very curious on your suggestions.