Thanks for the quick response.
Actually, I did try setting the "require SSL" attribute in IIS 7 for the "Sitefinity" folder. This did present me with a login to the Sitefinity admin area using the "https://mydomain.com/sitefinity" address. But, once user credentials are entered and submitted, the browser seems to be forced back to "http://mydomain.com/sitefinity" on the following page and fails.
This also has a side effect that seems to prevent the rest of the site from getting our CSS document located in \website_root\App_Data\Sitefinity\WebsiteTemplates\project_name\App_Themes\project_name\Global\main.css .
This made me think there may be some other explicit setting we need to make in order to prtect the Admin area with SSL, while allowing the rest of the site access to the CSS document.
Is there some other setting that explicitly calls the "http" version of the site for admin? We are using Windows 2008, 64-bit with IIS 7.
Thanks for your help.