Hi Adarsh,
Try the below as it has worked for me for a similar requirement
bape_vbap-vbeln = p_vbeln.
bape_vbap-posnr = '000010'.
bape_vbap-zzpump_reqd = 'X'.
t_exten-structure = 'BAPE_VBAP'.
t_exten-valuepart1 = bape_vbap.
APPEND t_exten.
bape_vbapx-vbeln = p_vbeln.
bape_vbapx-posnr = '000010'.
bape_vbapx-zzpump_reqd = 'X'.
t_exten-structure = 'BAPE_VBAPX'.
t_exten-valuepart1 = bape_vbapx.
APPEND t_exten.
Hope this helps!