Thanks for your advice, Ryan! This worked great for my needs.
Regards, Melissa
I'm assuming you want the login link to work, which is why you are doing the Location directive on /w/Special:UserLogin. So, what you can do is the following:
Redirect /w/Special:UserLogin https://<servername>/wiki/HttpAuthRedirect
<Location /wiki/HttpAuthRedirect> AuthType "basic" AuthName "wiki" AuthPAM_Enabled on AuthPAM_FallThrough Off SSLRequireSSL Require valid-user
</Location>
Then protect and edit HttpAuthRedirect, and put the following line into the page:
#REDIRECT [[Main Page]]
Your users will get two redirects when they log in, but it should work.
V/r,
Ryan Lane