PDF format report with Arabic characters ?

Hi all.
I generated a report with PDF format as output,But it couldn't recognize Arabic characters in PDF file and
it was converted to rectangle form.
How can I solve this problem?

Note :
Regedit Parameters in client:
NLS_LANG = 'AMERICAN_AMERICA.AR8MSWIN1256'
DEVELOPER_NLS_LANG='AMERICAN_AMERICA.WE8ISO8859P1'

Best Regards.