How to modify params of elements created using vc_map() [closed]

How can I update params of custom elements created using vc_map function. I can update the built-in elements as described the following link :
https://kb.wpbakery.com/docs/developers-how-tos/update-single-param-values/

While calling the WPBMap::getParam function I’m getting "false" as return. I think the "vc_after_init" hook is fired before the custom element is created.