RDP from external IP to KVM (WinSvr 2008)

Respected Proxmox Forum Users/Staff,

I had KVM installed with WinSvr2008 for my client.

As we all know that we could only use VNC to browse the KVM (WinSvr2008)

I need to connect to KVM using windows RDP and not VNC cause it is not permitted for my client to login to my Proxmox.

KVM network currently set to NAT and could browse internet from VNC.
At WinSvr2008 the configuration is DHCP and works fine if using DHCP. It is failed to accept connection/could not browsing/ping if i set the failover IP as static IP to WinSvr2008.

As far as i know that we need a static IP to connect to RDP (I had 5 failover IP that i could use to assign on the static IP)

Question :

>> How to assign static IP in current KVM so that winsvr2008 could accept the RDP request from external IP (my client)?

Is there anything related to bridging or setting eth0? if so how to set it? i saw that proxmox provide GUI to set it :
kindly take a look at this picture of Proxmox GUI for setting network : http://i.imgur.com/T6XPp9O.png

If it could not set through Proxmox GUI, any idea on how to set it on /etc/network/interfaces?

Looking forward for any though, thanks in advance for your time :)

Kind regards

Xen