That's not strictly true. Vodafone and Orange (to name but two) remove the VoIP functionality from the phone because they don't want you to use it.
My debranded Vodafone N95 8GB with the standard 20.0.016 firmware has options for "Internet telephony", I bet the Orange one doesn't...
wheres the internet telephony option? I have a debranded N958GB with latest firmware but cant find it.