This is how i am calling the function,
CALL FUNCTION 'SSF_KRN_SIGN'
EXPORTING
SSFTOOLKIT = l_SSFTOOLKIT
* STR_FORMAT = 'PKCS7'
* B_INC_CERTS = ' '
B_DETACHED = 'X'
* B_INENC = 'X'
* IO_SPEC = 'T'
OSTR_INPUT_DATA_L = datalen
STR_HASHALG = 'SHA1'
IMPORTING
OSTR_SIGNED_DATA_L = signeddatalen
CRC = crc
TABLES
OSTR_INPUT_DATA = lt_data_to_sign
SIGNER = lt_signers
OSTR_SIGNED_DATA = signeddata
EXCEPTIONS
SSF_KRN_ERROR = 1
SSF_KRN_NOOP = 2
SSF_KRN_NOMEMORY = 3
SSF_KRN_OPINV = 4
SSF_KRN_NOSSFLIB = 5
SSF_KRN_SIGNER_LIST_ERROR = 6
SSF_KRN_INPUT_DATA_ERROR = 7
SSF_KRN_INVALID_PAR = 8
SSF_KRN_INVALID_PARLEN = 9
SSF_FB_INPUT_PARAMETER_ERROR = 10
OTHERS = 11
.
IF SY-SUBRC <> 0.
MESSAGE ID SY-MSGID TYPE SY-MSGTY NUMBER SY-MSGNO
WITH SY-MSGV1 SY-MSGV2 SY-MSGV3 SY-MSGV4.
ENDIF.
Regards