How to make a custom node as an interface node in standard component

Hi Experts,

I am enhancing a standard FPM component for a requirement . In that process I would like to create a node and make it as an interface node . so that it will be reflected in the interface controller of the parent one  and I want to reuse this Parent component's node and attribute  in one of its child component. This is my idea. But, the main problem is when I am trying to make a custom node as interface node in standard FPM component, its not allowing me to do so.

please help me out .

Thanks,

Anand.