MUNDOSAP - matchcode a medida

Hola,

tengo este codigo de un matchcode, lo he implantado y al darle al f4 se ven los valores pero el select option no recoje el valor seleccionado.

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*MATCHCODE
*******DECLARACIÓN DE VARIABLES*********
DATA: BEGIN OF t_values OCCURS 0,
value(60) TYPE c.
DATA: END OF t_values.

DATA: BEGIN OF t_fields OCCURS 0.
INCLUDE STRUCTURE help_value.
DATA END OF t_fields.
DATA: valor(20) TYPE C.
DATA: BEGIN OF t_EBELN OCCURS 0,
EBELN LIKE zorders-ebeln,
END OF t_EBELN.

DATA P_EBELN LIKE HELP_INFO-FIELDNAME.

*DATA: BEGIN OF S_CG,
*FICTR LIKE ZAC_CG_SEC-FICTR.
*DATA: END OF S_CG.
*DATA: IT_CG LIKE S_CG OCCURS 0 WITH HEADER LINE.

*****EVENTO PARA QUE SE MUESTRE LA AYUDA *********
AT SELECTION-SCREEN ON VALUE-REQUEST FOR s_orco-LOW.

REFRESH: t_values, t_fields.
CLEAR : t_values, t_fields.

t_fields-fieldname = 'EBELN'.
t_fields-tabname = 'ZORDERS'.
t_fields-selectflag = 'X'.
APPEND t_fields. CLEAR t_fields.

SELECT ebeln
FROM zorders
INTO CORRESPONDING FIELDS OF TABLE t_EBELN.

SORT t_EBELN by ebeln.
DELETE ADJACENT DUPLICATES FROM t_EBELN.

LOOP AT t_EBELN.
t_values-value = t_EBELN-ebeln.
APPEND t_values.
ENDLOOP.

CALL FUNCTION 'HELP_VALUES_GET_WITH_TABLE'
EXPORTING
* cucol = 20
* curow = 4
tabname = 't_EBELN'
fieldname = 'ebeln'
IMPORTING
select_value = P_EBELN
TABLES
fields = t_fields
valuetab = t_values.