Outlook setup with proxy

How do I get sntp and pop3 set up to run with proxy 2.0 ie… getting out to real world want to use outlook with the account being hosted on yahoo so need to be able to down load mail. Right now I cant ping the out side world because of the way proxy is set up on the network. We had been hosting are own e-mail with exchange on a exchange server but do to down sizeing we no longer need to so we are doing this way Iam assumeing that its a permisions issue with proxy or the way we have proxy setupto run are network and access to the internet so is ther something we can disable or setup to make this work.(running NT with a T-1 Connection)