Default document not being processed when not included in URL

Running ColdFusion 9,0,1,274733 on JRun (J2EE install), Windows Server 2008 R2, Java 1.6.0_22

Has anyone else had a problem getting the default document, index.cfm, to work with ColdFusion? I'm assuming that this is only an issue because of our setup; different web server (IIS) and application server (ColdFusion). I can't imagine we are the only ones running this configuration. Are we?

So here is the issue.
If we request http://mysite.com/index.cfm it works.
If we request http://mysite.com/ it does not work and we get a 404.

I checked the web connector's log file on our IIS server and can see that it is sending the request to our ColdFusion server. The ColdFusion server is sending back the 404 error code but I can't figure out why. We have the default document set on our IIS server for index.cfm. We also have the <welcome-file-list> set to include index.cfm on our application server (web.xml).

From our web connector's log when we do NOT include index.cfm:

2012-11-01 13:37:22 jrISAPI[4544:3600]  ***HttpExtensionProc for JRun ISAPI Extension: uri is "/test/"
2012-11-01 13:37:22 jrISAPI[4544:3600]     HTTP_HOST: servername
2012-11-01 13:37:22 jrISAPI[4544:3600]  filtering /test/ (/test/) HOST=servername
2012-11-01 13:37:22 jrISAPI[4544:3600]  filterRequest:   no match
2012-11-01 13:37:22 jrISAPI[4544:3600]  ExecUrl: request received: URL=/test/
2012-11-01 13:37:22 jrISAPI[4544:3600]  ExecUrl Completion: 404, ErrorCode=2, URL=/test/.

From our web connector's log when we do include index.cfm:

2012-11-01 13:49:02 jrISAPI[9936:3600]  ***HttpExtensionProc for JRun ISAPI Extension: uri is "/test/index.cfm"
2012-11-01 13:49:02 jrISAPI[9936:3600]     HTTP_HOST: servername
2012-11-01 13:49:02 jrISAPI[9936:3600]  filtering /test/index.cfm (/test/index.cfm) HOST=servername
2012-11-01 13:49:02 jrISAPI[9936:3600]  filterRequest:   matched *.cfm
2012-11-01 13:49:02 jrISAPI[9936:3600]  ***IISWorkerThreadProc for JRun ISAPI Extension: uri is "/test/index.cfm"
2012-11-01 13:49:02 jrISAPI[9936:3600]     ALL_RAW: Connection: Keep-Alive
Accept: image/gif, image/jpeg, image/pjpeg, image/pjpeg, application/vnd.ms-excel, application/vnd.ms-powerpoint, application/msword, application/x-shockwave-flash, application (553)
2012-11-01 13:49:02 jrISAPI[9936:3600]  Headers and Values:
... and much more ...

We have gotten around this issue by using the URL Rewrite module in IIS to append index.cfm to the URL. It works but my gut keeps telling me that we should not need to do that for such basic functionality.

Is anyone else having this issue? How have you gotten around this?

EDIT adding some more info

Here is my site's web.config file contents from the IIS server:

<?xml version="1.0" encoding="UTF-8"?>
<configuration>
<system.webServer>
    <handlers>
        <add name="JWildCardHandler" path="*" verb="*" modules="IsapiModule" scriptProcessor="D:\JRun4\lib\wsconfig\1\jrun_iis6_wildcard.dll" resourceType="Unspecified" requireAccess="None" />
        <add name="hbmxmlHandler" path="*.hbmxml" verb="*" modules="IsapiModule" scriptProcessor="D:\JRun4\lib\wsconfig\jrun_iis6.dll" resourceType="Either" responseBufferLimit="0" />
        <add name="cfswfHandler" path="*.cfswf" verb="*" modules="IsapiModule" scriptProcessor="D:\JRun4\lib\wsconfig\jrun_iis6.dll" resourceType="Either" responseBufferLimit="0" />
        <add name="cfrHandler" path="*.cfr" verb="*" modules="IsapiModule" scriptProcessor="D:\JRun4\lib\wsconfig\jrun_iis6.dll" resourceType="Either" responseBufferLimit="0" />
        <add name="cfcHandler" path="*.cfc" verb="*" modules="IsapiModule" scriptProcessor="D:\JRun4\lib\wsconfig\jrun_iis6.dll" resourceType="Either" responseBufferLimit="0" />
        <add name="cfmlHandler" path="*.cfml" verb="*" modules="IsapiModule" scriptProcessor="D:\JRun4\lib\wsconfig\jrun_iis6.dll" resourceType="Either" responseBufferLimit="0" />
        <add name="cfmHandler" path="*.cfm" verb="*" modules="IsapiModule" scriptProcessor="D:\JRun4\lib\wsconfig\jrun_iis6.dll" resourceType="Either" responseBufferLimit="0" />
        <add name="jwsHandler" path="*.jws" verb="*" modules="IsapiModule" scriptProcessor="D:\JRun4\lib\wsconfig\jrun_iis6.dll" resourceType="Either" responseBufferLimit="0" />
        <add name="jspHandler" path="*.jsp" verb="*" modules="IsapiModule" scriptProcessor="D:\JRun4\lib\wsconfig\jrun_iis6.dll" resourceType="Either" responseBufferLimit="0" />
    </handlers>
    <defaultDocument>
        <files>
            <add value="index.cfm" />
        </files>
    </defaultDocument>
    <staticContent>
        <mimeMap fileExtension=".air" mimeType="application/vnd.adobe.air-application-installer-package zip" />
    </staticContent>
</system.webServer>
</configuration>

Here is some of the file contents from the APP server web.xml:

<welcome-file-list id="WelcomeFileList_1034546870672">
    <welcome-file>index.cfm</welcome-file>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.htm</welcome-file>
</welcome-file-list>

Solution

I also posted this question on the Adobe forums and it has gained more traction over there. You can read all of the details here.

It seems like the main issue I was having is that IIS was not passing '/index.cfm' to the web connector once it had determined that ColdFusion had no mapping for '/'. This began working after I created a blank (empty) index.cfm file on the web server. I do not recall having to place the CFM files on the web server when using distributed mode in the past. Can anyone confirm or deny that the CFM files need to reside on both servers for this to work (without using rewrite rules anyway)?