Hi Roch,
Another thing: if your mobile phone is set to auto it will always
register on its home network (if available) even if the signal of your
basestation is far stronger.
Can you specify home network?
Cause according to Harald and Dieter, a MS saves the latest ARFCN, LAC,
TMSI and some other parameters in the SIM in a so called Elementary
Files (yes, time to time I do my homework :p ). And since a mobilephone
is suppose to be mobile, than "home network" makes no sense to me. But
maybe I missed a chapter about how GSM works.