Habe es gelöst!
Es gibt einen Funktionsbaustein:
WA_BDCDATA-PROGRAM = 'SAPLCIC0'.
WA_BDCDATA-DYNPRO = '8100'.
WA_BDCDATA-DYNBEGIN = 'X'.
APPEND WA_BDCDATA TO BDCDATA.
CLEAR WA_BDCDATA.
WA_BDCDATA-FNAM = 'RJYCIC_SEARCH-GPNR'.
WA_BDCDATA-FVAL = <fs_itab>-kunnr.
APPEND WA_BDCDATA TO BDCDATA.
WA_BDCDATA-PROGRAM = 'SAPLCIC0'.
WA_BDCDATA-DYNPRO = '8100'.
APPEND WA_BDCDATA TO BDCDATA.
CLEAR WA_BDCDATA.
WA_BDCDATA-FNAM = 'BDC_OKCODE'.
* WA_BDCDATA-FVAL = '=UPD'.
WA_BDCDATA-FVAL = '=CSEARCH_CONTINUE'.
APPEND WA_BDCDATA TO BDCDATA.
CALL FUNCTION 'CALL_CIC_TRANSACTION'
EXPORTING
tcode = 'CIC0'
skipfirst = 'X'
tables
in_bdcdata = bdcdata
out_messtab = messtab.
* EXCEPTIONS
* NO_AUTHORIZATION = 1
* OTHERS = 2
.
IF sy-subrc <> 0.
* MESSAGE ID SY-MSGID TYPE SY-MSGTY NUMBER SY-MSGNO
* WITH SY-MSGV1 SY-MSGV2 SY-MSGV3 SY-MSGV4.
ENDIF.
Trotzdem danke für deine Hilfe!