GSM test sets (HP 8922M, for instance..)

There are a lot of HP/Agilent 8922M units for sale very cheap (less than US $500). I know that these devices can simulate a GSM base station, but does that simulation occur over the air, or do I need to connect my handset I am testing to the 8922M with a cable ? I know I need to get a 8322A expansion for the unit - any other details I should look out for ? Also, what is an equivalent test unit for WCDMA (3g) base station simulation (I know these will be more expensive). Thanks.