[Technix2002]

Here is what I did: tether to your host PC through USB then in the network adapter settings of VirtualBox choose PCnet-FAST III and use your "Windows Mobile-based Internet Sharing Device" as the bridged network adapter. It's what I'm using right now because my work has a proxy. Good luck and hit thanks if I helped (I don't have very many of those yet).

One more thing to check in order for it to show up in VirtualBox, make sure your "Windows Mobile-based Internet Sharing Device" (in the properties of the network adaptor and in the general tab) has "VirtualBox Bridged Networking Driver" selected (you might have to select, deselect then reselect again then click OK).