Setting seaches to run in a case sensitive manner
FDSE will perform all searches in a case insensitive manner by default ("Foo" == "foo"). To perform case sensitive searches, follow these steps:
Make sure you have at least FDSE version 2.0.0.0048, the first to use the advanced Character Conversion settings.
Go to "Admin Page" => "User Interface" => "Language and Locale Settings" => "Character Conversion Settings".
From that page, toggle from "Case Insensitive" to "Case Sensitive".
Rebuild all of your index files.
History: applies to FDSE version 2.0.0.0048 and newer.
"Setting seaches to run in a case sensitive manner"
http://www.xav.com/scripts/search/help/1105.html