Using Gmail as a webmail interface - SMTP issue

[GravyMonster]

Hey all,

I've setup Gmail as a web interface for my email address. However when I send an email it gets an ugly 'from: [email protected] on behalf of [email protected]' message.

I know to remove this I need to let google use my smtp server, however when I do that and give it the server name, port, username and password Gmail gives me the error:

We are having trouble authenticating with your other mail service. Please try changing your SSL setting. If you continue to experience difficulties, please contact your other email provider for further instructions.

Changing the SSL setting does nothing. Does anyone know what this issue is and what I can do?