About WAK3

Hi everybody

I have some problems

I try to get information about Plant Groups and Plant Class the TX WAK3 can do that but I would like to do the same thing in my Z program. Somebody knows the way the TX WAK3 works . Maybe through a BAPI or Special Function

My program should work like that :

Enter Promotion Number ( AKTNR ) and then I want to get the Plant group and after that all theirs Plant class (center )

Can Anybody help me!