Openworld not BTinternet

I have always had one of the original @btopenworld addresses. I have been giving out my address as @btinternet to new contacts as the two are interchangeable, I know. But when I log onto the web page as @btinternet I always get an @btopenworld page and mail is sent using the latter. Is there a way of getting my webmail to send as btinternet? I have been mailed recently by two new contacts asking which is correct (ie I gave btinternet when registering with a company and then emailed them from the web, which came out as btopenworld.) So far I haven't found a way of ditching openworld in sent emails - would a new account in Windows Live do it, I wonder. I do like the web interface though.

Webmail will be more limited, tried using a mail client like Outlook, which gives you more control over things like this.

On the webmail, I have both addresses listed and can choose the default.

Go to Options at the top, then mail options. Click on Mail Accounts on the left, then in the middle column it should list the two accounts, I have Mail and Mail Extra Address. If you click on the BTInternet account there should be a box there to tick to make it the default sending account. Then click the yellow save button.

Hope that helps!

Andy