joya! voy en buen camino entonces!!
Ahora si pongo esto..
SELECT spmon sptag vbeln pkunag pkunre matnr fkimg
INTO TABLE it_s900
FROM s900
FOR ALL ENTRIES IN it_ausp
WHERE matnr EQ it_ausp-matnr
AND sptag IN s_sptag
AND fkart IN s_fkart
AND pkunag IN s_pkunag
AND pkunre IN s_pkunre
AND waerk EQ p_waers.
IF sy-subrc EQ 0.
sort it_s900 by vbeln.
SELECT a~vbeln a~fkart a~waerk a~vkorg a~vtweg
b~posnr b~pstyv b~werks b~wavwr b~kzwi1 b~kzwi3
INTO TABLE it_vbrk
FROM ( vbrk AS a
INNER JOIN vbrp AS b
ON a~vbeln = b~vbeln )
FOR ALL ENTRIES IN it_s900
WHERE a~vbeln EQ it_s900-vbeln
AND a~vkorg IN s_vkorg
AND a~vtweg IN s_vtweg
AND a~bukrs EQ p_bukrs
AND b~pstyv IN s_pstyv.
sique siendo performante??