I have exactly the same problem, I success to configure my SIP settings, but then i don't know how to use it. I can't find the Menu > Settings > Connectivity > Administrative settings > Net settings. (I've installed the SIP_VoIP_3_1_Settings_S60_5_x_v1_0_en.sis)
Is it somebody here who can help us, I’m quite desperate :'(
If it isn't natively possible, is there a software which can help?
Thank a lot for your help !