Thanks you for your quick reply,
We have alsready installed the website as a custom php application and set the prefix alias rewrite as describe, according to the bitnami doc guide.
All the links point as if the website is installed on the root "mywebsite.com/..." instead of the excepting "mywebsite.com/hosting".
Note : When we configure the apache server to set the Whmcs folder as the root folder, all the system is well working.
Support tool :
Let me know if you need additionnal information,
Thanks you for you help,