IE5.1 for Macintosh falls short using OWA for email

[Guest_imported]

I have not been able to obtain a higher release of Internet Explorer than 5.1 for MacIntosh. With the IE5.1 release for MacIntosh you do not have the option of clicking on the "TO...", or "Cc..." , or "Bcc..." hyperlinks
which would bring up the window:
"Find Names - Web Page Dialog"
There you would selectively search for your target e-mail address from the Exchange 2000 Global Address List. With IE5.1 for MacIntosh you must manually enter the entire e-mail address. My thought is that Microsoft may not fully support OWA for MacIntosh workstations.

Does any one know if there is an IE release that would yield the same support as IE6 for Windows clients?

Is there a full technical answer/documentation that explains why the support is not provided if that is the case?

I work for a school system that is moving to PCs but has many legacy MacIntosh systems. Additionally, I am currently running Microsoft 2000 Advance Server with service pack 2 installed and Microsoft Exchange 2000 Enterprise Server with its service pack 2 installed.

Thanks.