IIS 7.5 Range Request

I am trying to get IIS7.5 to be able to handle range request for a mp4 file.  When a request is made, I get back a 200 status code, but I believe I am looking for a 206.1.  Has anyone had any luck with getting range request to work properly?  Any ideas are much appreacited!

Example response header:

HTTP/1.1 200 OK

Content-Length: 4103155

Content-Type: video/mp4

Last-Modified: Tue, 30 Oct 2012 10:13:44 GMT

Accept-Ranges: bytes

ETag: "c22z502a55c1ch1:0"

Server: Microsoft-IIS/7.5