Visual Composer - 覆盖类

I'm working on a Wordpress website using Visual Composer (WPBakery).

I had to modify some classes in the core of the plugin, for example,

I modified this class : WPBakeryShortCode_VC_Tta_Section

The problem is I had to modify functions in the core of the plugin (shortcodes/vc-tta-section.php).

I didn't found any solution to overwrite a class of Visual Composer. Even If I extends this class and add my own code, I would have to call my own class, but didn't found anything in the code that could help me to modify base class used WPBakeryShortCode_VC_Tta_Section to WPBakeryShortCode_VC_Tta_Section_CUSTOM for example.

Thanks for your help