I took a quick look at your ISP providers website to see how they require your username to be entered in and it looks like you're correct in using the full address for the username.
That being said, if your password is entered in correctly and there are no typos, it might be that your mail provider doesn't support emails being sent for SMTP from a source other than traditional email. While this isn't common, it looks like this is the case for your email provider. You might want to give them a call and explain that you are trying to use their SMTP server from a web application and see if this is supported.
If it isn't supported, don't worry. Sign up for a free Gmail account. Gmail allows you to use their SMTP server for free. Got to love Gmail. Once you sign up for an account, type in the Gmail information for your email settings. This will basically means you will use Gmail for your outgoing emails.
One important thing to understand is that just because you're using Gmail's SMTP, doesn't mean you can't use your normal email throughout Method. Gmail is just used as the delivery means to send your company emails.
Just my 2 cents :)
Danny Do Couto
Chief Operating Officer
Method Integration Inc.