Unable to send email using SMTP connect and BT Broadband SMTP server

I've configured our exchange server to recieve mail and now i'm looking to configure it to send mail via the BT Business Broadband SMTP server.

I've created a new SMTP connector and set it to forward to mail.btconnect.com. I've left the address space as * at a cost of 1. Under Advanced I've place our login credentials under Basic Authentication and i've not changed anything else.

When i send an email I can see them queing up. Any ideas why they're not being delivered?

Solution: Unable to send email using SMTP connect and BT Broadband SMTP server

Also,

http://www.experts-exchange.com/Networking/Protocols/Application_Protocols/Email/SMTP/Q_23572760.html

points that BT dont require authentication if you have had your domain allowed....? May be worth a go