Serial Ports using HyperV in Ubuntu guest OS

I need to run a terminal session (term) from within the guest OS, Ubuntu 12.04.3 LTS to a serial port on the Windows 8.1P host. In my case a USB to serial adapter that Windows has mapped to COM5.

I don't really know where to start.  In HyperV, under Settings, I see a Com1 and Com2 under hardware. The two options are None or Named pipe.  Not all that clear what to do here.

Presumably this is what will be visible to Ubuntu as  /dev/ttyXX   ??

Can anyone point the way to map a serial port into Ubuntu?   Or a suitable workaround?

Thanks.