Error 404.2 trying to serve index.cfm as directory default page

Hello,

Here is my server

- Windows 2008 Server R2 Ent

- IIS 7.5

- ColdFusion 10

CF10 installation ran smoothly, the wsconfig seems to have created all necessary stuffs like :

ISAPI filter : tomcat C:\ColdFusion10\config\wsconfig\1\isapi_redirect.dll

ISAPI restriction authorized : tomcat_all C:\ColdFusion10\config\wsconfig\1\isapi_redirect.dll

index.cfm added in Document by default, placed at first place up in the list

cfide, jakarta virtual directories created, etc..

Everything is running ok EXCEPT that IIS is unable to server index.cfm as a directory default page :

- this generate an error : http://www.example.com/ (to simplify, index.cfm is the only page in root directory)

- this doesn't generate an error and serve the index.cfm page correctly : http://www.example.com/index.cfm

Error 404.2 is talking about (in french)

"La page que vous avez demandée est introuvable en raison des paramètres de la liste des restrictions ISAPI et CGI du serveur Web."`

I don't see anything special in ISAPI/CGI restrictions parameters, they are even the same as on the dev server which doesn't have the problem...

I tried to remove the connectors by running wsconfig and then re-run to reinstall the connectors, without success.

Any help appreciated as I'm running out of idea...

Thank you.