Assisted GPS, SUPL

How to configure properly Assisted GPS?
Assisted GPS mode is configured with parameter fixtype of at!GpsFix and at!gpsTrack
But it doesn’t work: No coordinates at all or TTFF is longer than in standalone mode.
Also there is command at!GpsSuplUrl.
Is it required? How to use it?



What unit is this, implication it is an SL8? Assuming it is not sure anything other than the 1xtra service has really been used for assistance.



The unit is WP7607.