Check these two links:
http://support.dell.com/support/edocs/systems/ins1520/en/sm/keyboard.htm#wp1179937
http://support.dell.com/support/edocs/systems/ins5100/en/i5100-om.pdf (This is the manual, the guide with pictures starts on page 109).
This info should be enough for you to be able to do it yourself. Also, it would be great if you could [http://www.ifixit.com/Guide/new|create a repair guide for iFixit] for doing this. It'd be a great help to people later on who want to be able to do this