Hi Cristina,
There may be a case where the above field has been disabled,,,
check table:- T588M and under
Module Pool:- MP000800
Screen:- 2000
Feature :- P0008
Variable Key :-Blank
Alt Screen:- 2000
Next Screen :- 0
look out for PA0008-TRFGR... This field should be selected under "std" option..
Regards,
Veeram