Diagnosis
Function module ZZ_USEREXIT_PARTNER does not exist

System Response
You can only maintain a new partner type if this function moduleexists.

Procedure
Enter the function module ZZ_SD_USEREXIT_PARTNER in a new functiongroup
in the customer reserve function group.
You call up partner types Y* and Z* for processing as follows:
CALL FUNCTION 'ZZ_SD_USEREXIT_PARTNER'
EXPORTING I_NRART = TPAR-NRART (STRUCTURE TPAR-NRART)
I_VTCOM = VTCOM (STRUCTURE VTCOM)
IMPORTING I_LKUPAV = LKUPAV. (STRUCTURE KUPAV)
The partner type is in the field I_NRART.
The partner number is in the field I_VTCOM-ABLAD.
Depending on the environment, you can use the fields I_VTCOM-VKORG,I_VTCOM-VTWEG and I_VTCOM-SPART.
For example, you could define a partner type which checks against a newtable.
Example: FUNCTION.
TABLES: T999.
SELECT SINGLE * FROM T999
WHERE PARTNER = I_VTCOM-ABLAD.
IF SY-SUBRC = 0.
I_LKUPAV-NAME1 = T999-NAME1.
ENDIF.
* Depending on the circumstances, you can decide whether to send output
* or not.
CASE I_VTCOM-MSGKZ.
WHEN 'U'.
WHEN 'S'.
MESSAGE S200 WITH I_VTCOM-ABLAD.
WHEN 'I'.
MESSAGE I200 WITH I_VTCOM-ABLAD.
WHEN 'W'.
MESSAGE W200 WITH I_VTCOM-ABLAD.
WHEN ' '.
MESSAGE E200 WITH I_VTCOM-ABLADRAISING NO_PARTNER.
ENDCASE.
CASE I_VTCOM-MSGKZ.
ENDFUNCTION.