Hi,
I used this feature now the first time with the gps logger and there is a diffenrece in the costs. I have to pay for the data amount and wondered if the lat lon speed and alt have to be this accurate? I mean if you transmit only 5 or 6 digits right of point it would be enough, or wouldn't it? There is no problem to shorten it at the server side but why transmitting 52.50779166666667 when 52.50780 would satisfy in the first place. AFAIR shorten it to 5 dezimal places means pos+-12cm. If requested I'll calculate it exactly.
It is possible to do real-time GPS tracking using BT747. This is different from GPS Logging which can be considered as Deferrred GPS Tracking as you can get the track at a later time. Working with differential tracks is the main function of BT747, but live tracking is provided in the Desktop version and the Mobile Phone version (J2ME).