To get a static ip address, mask and gatway when running in WINPE 2.0:

From the WINPE 2.0 command prompt run in the following order:

netcfg /winpe
wpeutil InitializeNetwork 
netsh interface ipv4 set address "Local Area connection" static youripaddress yourmask yourgateway 1

e.g. 
netsh interface ip set address name="Local Area connection" static 192.168.0.122 255.255.255.0 192.168.0.1
netsh interface ip set address name="" static 192.168.0.122 255.255.255.0 192.168.0.1

You can add dns and wins as well:
e.g.
netsh interface ip set dns name="Local Area connection" static 192.168.0.1
netsh interface ip set dns name="" static 192.168.0.1

