subtype for custom infotype

Hi all,

I have cloned infotype 442 to 9442, as per client requirement. 442 has a subtype list, I am not able to replicate the same for 9442.

I have entered the same on V_T591A but the maintainance view appears different for 442 and 9442. For 9442 I donot have the "Object identification permitted for subtype" check mark.

How do I get this to work?