Mobile internet settings are very much service provider dependent.
Sony Ericsson maintains a support service that keeps track of the operator internet configurations and, when you enter your mobile phone number, the webpage sends an SMS to your phone which sets the your default internet settings of your service provider. This might not be appropriate for everyone (e.g. I am using a corporate subscription in which we use non-default internet access point name).
On the k750i the default internet profile can be downloaded from the mobile menu itself.
This information comes from the sony ericsson support page:
- From standby screen, select 'Main menu' --> Control panel --> Connections.
- Open Internet wizard, and tap 'Accept' to download the settings.
The first time you start your phone or insert a new SIM card, the Settings download is triggered from the start-up wizard.