You can get the function by changing the product code of your N95, and then getting the generic firmware, your service provider will have modified the firmware to remove this function. I know Vodafone have and might eventually put it back in at a later date, they removed it as they said that their services do not work with this function... Which is stupid.
By the way changing your product code, is not only risky you can brick your phone, but it also voids warranty. So unless its desperate no point in doing it.