BAPI_PO_CREATE1 system wrong when Create item text and header text

data: i_potextitem LIKE bapimepotext OCCURS 0 ,

wa_potextitem LIKE bapimepotext.

• text information

wa_potextitem-po_item = 10.

wa_potextitem-text_id = 'F01'.

wa_potextitem-text_form = '*'.

wa_potextitem-text_line = 'test'.

APPEND wa_potextitem TO i_potextitem.

CALL FUNCTION 'BAPI_PO_CREATE1'

EXPORTING

poheader = wa_poheader

poheaderx = wa_poheaderx

TABLES

return = i_return

poitem = i_poitem

poitemx = i_poitemx

potextitem = i_potextitem

.

when I run it , come out the follow thing in the return message.

A ME 009

System error (text name empty in text object EKPO and text ID F01).

when i do not pay the focous on potextitem, it runs well.

I don't know whether it's a system's bug,

my version is 4.6c