Need to add fields PERSG and PERSK to feature 40ECS (structure PMEAL)

Dear Experts,

Need to add fields PERSG & PERSK to feture 40ECS to achieve a client requirement. Abapper has already appended structure, but IT0008 is throwing error as expected.  We understand this would require program correction, but not sure how to achieve this.

My question are:

How to create a Z feature which functions in line with 40ECS +added fields. How to activate it.

What are the challenges can we expect while creating Z features.

Appreciate a timely reply.

Thanks

Archana.N