I use a Fritzbox VPN Server, but modified that my iPhone can use it:
AVM - VPN-Verbindung mit Apple iOS (z.B. iPhone) bzw. Mac OS X zur FRITZ!Box (Client-LAN-Kopplung)
(don't know if this exists also in english)

But how can I connect now with my HP Touchpad too? It seems not to work

Hope someone can help me!