Custm module for New User Panel

Hello,
we're trying to develop a simple module for Client web panel but we're not able to add any menu item editing the file:

/usr/local/cwpsrv/htdocs/resources/client/include/3rdparty.php

Moreover, if we directly open the module added on the following directory:

/usr/local/cwpsrv/htdocs/resources/client/modules/

with URL like http://IP:2082/USER/index.php?test2.php

the html code is added at the beginning of the page.

Is there any new procedure to develop a module on New User Panel ?

Thanks,
Sebastiano.

the same problem applies to me