VPN with Android

Hello,

did somebody have any experience with the new VPNServer Class in Android 4.x and use it with Xamarin?

http://developer.android.com/reference/android/net/VpnService.html

There is an example, called: ToyVPN in the android sdk examples.
But there is nothing about the use of IPSEC/L2PT and PSK.

So maybe have somebody an better example how i can connect to such a service.
Or how to use the IPSec/L2PT functionality of Android with Xamarin (because there is a VPN Wizard on Android itself, maybe i can use it from code too?).

Thank you