To generate PDF on save of Purchase Order

Hi All,

My requirement is to generate PDF on save of purchase order. I have chosen transmission medium 'special function' for the same.Following is the code snippet

IF NAST-KSCHL = 'ZEU' AND NAST-NACHA = 8.

    DATA : LV_ITCPO TYPE ITCPO.

    LV_ITCPO-TDNOPRINT = 'X'.

    LV_ITCPO-tdgetotf = 'X'.

    LV_ITCPO-TDNEWID = 'X'.

    LV_ITCPO-tdnoprev = 'X'.

      CALL FUNCTION 'OPEN_FORM'

       EXPORTING FORM = XFORMULAR

                 LANGUAGE = EKKO-SPRAS

                 OPTIONS = LV_ITCPO

*                 ARCHIVE_INDEX  = TOA_DARA

*                 ARCHIVE_PARAMS = ARC_PARAMS

*              ARCHIVE_PARAMS = ALARC_PAR1

                 DEVICE = 'PRINTER'

                 DIALOG = ''

       EXCEPTIONS CANCELED = 01.

  IF SY-SUBRC NE 0.

    PERFORM PROTOCOL_UPDATE USING '142' EKKO-EBELN SPACE SPACE SPACE.

    RETCO = SY-SUBRC.

    EXIT.

  ENDIF.

This is followed by WRITE_FORM and CLOSE_FORM and I have used FM CONVERT_TO_OTF ,GUI_DOWNLOAD to get PDF.

So now I am able to get PDF if select dispact time as 'Send with periodically scheduled job' and by running RSNAST00. But I am getting error 'express document update was terminated received from author' if I  select dispatch time as 'Send while saving the application. Upon looking below is the message for this.

Should I need to add anything so it works for 'Send while saving the application' too.

Thanks,

Gowrinath.