Q. http://username:firstname.lastname@example.org doesn't work anymore!
A. That's right. Around 2/2004 Microsoft issued a security update for IE which disallows this form of URL.
The most likely workaround is to convert to using forms-based/cookie login, and modify the easyloginnow.asp to accept the username/password from the source of your choice, rather than the usual login.htm page.
For example, instead of using
then grab the u/p out of the url string, and use these to set the cookie for cookie-based login.
Be aware that this method of passing in a username and password is vulnerable to simple copy/paste attacks,
whereby the URL can be posted on forums to effectively destroy your security.