[ubuntu] Access host OpenVPN tap0

I have a computer running Ubuntu 12.04 64bit, which uses OpenVPN and a TAP adapter to connect to a VPN server.

This computer runs VirtualBox in which I have a virtual machine running Ubuntu 10.04

Is there a way to make the Virtual Machine to access the computers in the VPN network?

The network card of the Host is already accessible to the Guest, and the Guest gets an IP address from my router and gets internet access.

Thanks