relation between table IBIB and IBPART

Hi everyone.

I know a relation from IBPART to IBIB (IBPART ËIBIB).

when I relate both of two tables,I use function module "guid_convert" and convert Ibpart's segment recno(16).It is totally match with ibib's recno(22).

However,I cannot do a same thing from IBIB to IBPART

(IBIBËIBPART)

When I use "guid_convert" and convert ibib's recno(22),

EV_GUID_X16 is totally different from Ibpart's segment recno(16).

I would like to know how to relate IBIBËIBPART.

IF anyone know about it,please help me.