I came across this on the BMW bluetooth

http://www.e38.org/BMW-03_00-Voice-Control-en.pdf

(pg 10)

The names and telephone numbers
entered in your voice control
phonebook are independent of the
telephone or SIM card memory of your
BMW car telephone or BMW mobile
phone.
In other words, it is not possible to call
up the numbers stored in the telephone
itself or on the SIM card by voice input,
nor is it possible to store numbers there
by voice input.


But people in here have being able to do it.