where is socket.io.js?

Possible Duplicate:
socket.io.js not found

I installed a simple web-chat demo: https://github.com/sorensen/node-chat-demo

and I want to connect to it via an apache proxy server, so that instead of:

http://ip.address:3000/...

the address will be:

http://proxy.server/erel/...

This works for the static pages, for example, the address:

http://proxy.server/erel/javascripts/chat.js

correctly translates to:

http://ip.address:3000/javascripts/chat.js

However, it does not work with socket.io.js:

http://proxy.server/erel/socket.io/socket.io.js

does not translate to:

http://ip.address:3000/socket.io/socket.io.js

because socket.io.js is not actually there...

so where is it?