Install TMG on ESX server with one NIC

Hi Dear all
I have a problem with TMG
We have ESX server (with one NIC) that I create a new VM on it and install windows 2008R2, next install TMG 2010 but after install it seems need two NIC.
I create a new virtual NIC on vSphere and assign it to the VM, now I have 2 NIC on this server (LAN,WAN) 

LAN range IP    192.168.X.X 
Sub-net         255.255.255.0 
DG              blank
-------------------------
WAN range IP    91.98.X.X 
Sub-net 255.0.0.0 
DG      91.98.X.X


Is it possible just with one NIC do this job and after that all LAN clients coming beyond the TMG?

Please explain with detail ,I'm newbie !!!