Not in that part of the dialog box I don't believe.
If you are using premise based Exchange, you can choose the credential source that applies to this box, either user/password from one of the other services, or system account on Windows.
If you're using modern authentication, which is what that looks like to me as it appears to be setup for autodiscovery, then an account name there wouldn't do anything. Jabber parameters guide notes that with modern auth the other parameters don't take effect. I assume it just uses the email address that you've signed into Jabber with. If you're not using email for discovery but some other format that would be problematic.
I believe otherwise the customer would have to specify whatever should be in there to enable that feature. Its not the best integration given the state of other applications today, but, is how Jabber is.
