More Sat Nav

[crainneag]

Hi, I have a Siemens SATNav installed with the signal fed from the rear mounted aerial of my 406 estate. Anyone know how easy it would be to get to the aerial input connection so that I could insert a 'T' piece and run an aerial feed to a real GPS unit mounted on my dash. (Real= doesn't talk to me , allows me to bookmark where I am , gives me a map or a compass).