ME59: Problem updating partners in EXIT_SAPMM06E_012

Hi experts,

I'm trying to update the partners when creating the PO via ME59.

Because there are multiple partners in the contract, ME59 is not able to determine the correct partners, so I generate them in EXIT_SAPMM06E_012.

I add partners 'BA' and 'RS' ('LF' is already there), and after the execution of ME59, I see the three partners in EKPA... but in ME23N, I only see the 'BA' and 'LF' partners.

What am I doing wrong?

I update the partners using a symbol assigned to '(SAPLEKPA)XMMPA[])'. I got the same result using the function MM_CALL_UPDATE_PARTNERS.