How to create new subtypes for OM infotype 1002?

Gurus,

I have a requirement to create four new subtypes (to different texts ) for OM infotype HRP1002.

Let me know the procedure to achieve this.

I looked in subtype table T591A and T591S, but couldn't find any subtype (even the standard ones like 0001,0002,0003 etc) for 1002 infotype.

Thanks,

Amit Jain