var profile = new VpnNativeProfile();

profile.AlwaysOn = true;
profile.NativeProtocolType = VpnNativeProtocolType.IpsecIkev2;
profile.ProfileName = "My Profile";
profile.RememberCredentials = true;
profile.RequireVpnClientAppUI = true;

var agent = new VpnManagementAgent();

agent.ConnectProfileWithPasswordCredentialAsync(profile, new PasswordCredential
{
      UserName = "test_username",
      Password = "test_password"
};