./mining_proxy.py -o stratum.bitcoin.cz -p 3333 -gp PORT_TO_SET_IN_BLADE_CONF
I think this is the minimum for what you would need on the proxy. Make sure you are pointing at your local ip with the proxy and not slushes pool. You probably know that.
To re state, you should use your worker details from your slush account: user_workerid,pass:user_workerid:pass