From what I understand PPTP and L2TP are less secure than OVPN.
The 68U will generate its own complete .ovpn client with a 1024 cipher
Im new to this VPN stuff but was able to set up the keys required for 2048 cipher. I have a rough guide a few pages in OVPN @ 2048. You can skip the cert creation is you want the default 1024 cipher.
I am working on a better guide and should have it ready soon, A day or two.