IIS Dispatcher invalidateHandler

According to the documentation here:  https://dev.day.com/docs/en/cq/current/deploying/dispatcher/disp_config.html

You should be able to call a script specified in the property /invalidateHandler in the /cache section of the dispatcher config, but it does not appear that my script is being called when dispatcher receives invalidate.cache calls.  I am using dispatcher version dispatcher-iis-windows-x64-4.0.11 on Windows 7, IIS 7.5, CQ version 5.5.

I have a simple Windows batch script (.bat file) I am trying to call which finds and deletes files in my IIS doc root.  When I call it via command prompt in Windows it works as expected, and I have verified that permissions on the script file and directory where it is located should not be an issue.  The line in my dispatcher.any file is just after the /invalidate block within the /cache element, and looks like this:

    /invalidateHandler C:\inetpub\scripts\jsoninvalidator.bat

I have also tried putting double quotes around the file name, but no change.  

I see the following in my dispatcher log:

[Tue Mar 04 11:34:29 2014] [warn] C:\Inetpub\Scripts\dispatcher.any:200: entry not recognized: 'invalidateHandler'

Is invalidateHandler supported in the IIS version of dispatcher?  If so, in the version I'm using?  If so, any ideas of what the issue may be?  

Thanks!!