Enhancement of Standard Infotype 4000(Applicant Action)

Hello Experts,

I have got a requirement in PA-Personnel Management System to enhance the standard Infotype 4000 to add some additional fields on the particular screen of PB40 such as Interview date, time,venue etc. When HR admin select the action 'Invite Applicant' , HR admin would able to put some more additional details along with the standard fields.

I have got an error 'Infotype 4000 can not be Enhanced' while following these steps:

•Go to PM01. Select “Single Scrn” tab and enter Infotype no & Infotype Version.
•Select radio button “Customer Include”
•Clicked on “Generate Objects” .

I found that in structure PS4000 there is no standard Include.

Please suggest how to fix this problem.I am waiting for your valuable inputs...