新增字段需在以下表/结构中添加
    表：vbak/vbap
    结构：BAPE_VBAK、BAPE_VBAKX、VBAKKOZ、VBAKKOZX/
    BAPE_VBAP、BAPE_VBAPX、VBAPKOZ、VBAPKOZX

    BAPI(例):
    wa_valuepart = wa_bape_vbak.
    iw_extensionin-structure = ‘BAPE_VBAK’.
    iw_extensionin-valuepart1 = wa_valuepart(240).
    iw_extensionin-valuepart2 = wa_valuepart+240(240).
    iw_extensionin-valuepart3 = wa_valuepart+480(240).
    iw_extensionin-valuepart4 = wa_valuepart+720(240).
    APPEND iw_extensionin TO it_extensionin.
    CLEAR iw_extensionin.
    wa_valuepartx = wa_bape_vbakx.
    iw_extensionin-structure = ‘BAPE_VBAKX’.
    iw_extensionin-valuepart1 = wa_valuepartx(240).
    iw_extensionin-valuepart2 = wa_valuepartx+240(240).
    iw_extensionin-valuepart3 = wa_valuepartx+480(240).
    iw_extensionin-valuepart4 = wa_valuepartx+720(240).
    APPEND iw_extensionin TO it_extensionin.