IIS Redirect For Maintenance

we have an ecommerce application that needs to come down for
maintenance. The application is normally only accessed via
http://www.mydomain.com/virtualdir/aspfile.asp.

I'm using W2K Advanced Server/SP4.

I would like to create a generic HTML page that can easily be put on the IIS
server to redirect all users that access any files on this domain to my
maintenance page.

Originally, I thought I could create a directory called "maint" or whatever
from root and from the "Directory" tab within IIS Manager, change the URL to
redirect to a specific page and set the checkbox (directory below current or
whatever). This appears to work, as long as no virtualdirector or specific
ASP file is referenced at the end of the URL.

Does anyone know the best way to handle this without making a bunch of
permanent changes? My site will be down about 6 hours and I need a
maintenance page to display during this period.

BTW, I do have other banking sites that have their own logon/password form
on their site. Their sites <FORM> action attribute points to my server.