i would like to do that in order to keep an index.(html version) of our site working while editing the MODX site. IS that possible ?
You should be able to keep the index.html intact and untouched while working on the index.php (modx) version. You will be able to access both versions by typing each one in, ie: yourdomain.com/index.html or yourdomain.com/index.php.
Depending on your host, it will be set up to look for certain file types first. In my experience, my host has looked for index.html first, then index.php, etc. If there is no html, it will go down the list.
