I don't want copy of file during overwriting

My problem is that if i try to overwrite a opened file, pdfcreator generate a copy of the original file with suffix “_2”.
What i have to set (and where) to do sure that the program don’t generate a copy of an opened file?
I want that windows (or pdfcreator), give me a pop-up  “YOU CAN’T OVERWRITE ALREDY OPENED FILE”, like all other program that run on windows.