Attachment of forms in camunda 8 is not working with Form -Key

Hi Everyone ,
When we implement Form in task (Camunda 8 SaaS)then we have two options to select:-
1. Camunda Forms
2. Custom form Key
when we select first Camunda Forms we give data in JSON format that is working fine .
when we select second Custom form key we need to give Form Key So what format to give for Form key and what key should I pass in that, I already followed but not able to fetch data forms docs .
I gave my form Id as formKey as it was not working then I gave form id with (zeebe:formKey and io.camunda.zeebe:formKey), It is also not working. Any help or suggestion is appreciable .

@Avinash_Rawat I’m struck at same prob… did you find the solution?

No @Arjun1007 Still not waiting for response