diff --git a/INSTALL.txt b/INSTALL.txt
index e91568f..f4a0554 100644
--- a/INSTALL.txt
+++ b/INSTALL.txt
@@ -7,7 +7,13 @@ REQUIRED:
 
 $conf['stage_file_proxy_origin'] = 'http://example.com'; // no trailing slash
 
-The origin website.
+The origin website. If the site is using HTTP Basic Authentication the (browser
+popup for username and password) you can embed those in the url. Be sure to
+URL encode any special characters:
+
+For a username of myusername and password letme&in the configuration would be:
+
+$conf['stage_file_proxy_origin'] = 'http://myusername:letme%26in@example.com';
 
 OPTIONAL
 ========