Sony Ericsson C905 - SIP settings

[Jadtiff]

Hi, I have a Sony Ericsson C905 cell phone. I entered all the SIP settings from my company. The only problem I have is that I cannot make an Internet Telephony call. Do I need a software client on the C905 to make an Internet Telephony call? I called Sony Ericsson (SE), they said I must speak to Vodacom my SP... They said speak to SE. All help will be appreciated! Many thanks.

 

[upup]

Is that like a skype call or video call. or what is internet telephony call.