Integrated Messaging to an Externally hosted Email service

I have a client with a US500 that wants to use the Integrated Mesaging feature. He doesnt have an Exchange server, but uses a hosted email service. The issue is that the user login is user@hosteddomaun.com, & the CUE will not accept the @ symbol in the Username field. Anyone have an idea for a work-around?

Comments
If you configure the SMTP
If you configure the SMTP details via the CUE CLI it will take the @. You need to login to the router CLI and then start a session to the service module that will give you access to the CUE CLI.
smtp2go?
My company uses a service called smtp2go to relay emails.