You can modify the default profile for new users by loading the hive at %SYSTEMROOT%/Profiles/Default User/User.dat. Call it AAAA. Navigate to:
Add Key name Internet Connection Wizard with a blank Class.
Select the Internet Connection Wizard key and Add Value name Completed and set this type REG_DWORD data value to a 1 (true). The default is 0, (false).
Select AAAA and unload hive.