By default IIS7 doesn't have a icon to control FastCGI, but you can modify the values in the command line.  I'm using php as the example as that is the most common use for FastCGI.

appcmd set config -section:system.webServer/fastCgi /[fullPath='C:\php\php-cgi.exe'].activeTimeout:600

Replace the fullPath with your actual executable path.  The Timeout value is in seconds, so this sets it to 10 minutes.

Check to see if the values were imput correct with this command:

appcmd list config -section:system.webServer/fastCgi

You can also use Microsoft's installer for php.  This will give you a FastCGI icon in IIS you can use to configure these settings.