Yes it is possible.
First, you need to setup a RADIUS server on Win2003 (you can use the built in Internet Authentication Service (IAS)).
Once you have your RADIUS server configured, create a aaa authentication group for your radius server:
aaa-server AuthOutbound protocol radius
aaa-server AuthOutbound host 172.18.124.111 cisco
Then point your ssh authentication attempt to use RADIUS:
aaa authentication ssh console AuthOutbound
This document details setting up the IAS for VPNs. The concept is the same for shell access.
http://cisco.com/en/US/products/hw/vpndevc/ps2030/products_configuration_example09186a00800b6099.shtml
This one explains setting up AAA for SSH:
http://www.cisco.com/warp/public/110/authtopix.shtml#aaaauthsshconfig
