Affects Version/s: 1.8
Fix Version/s: 2.0
UFPDF does not have support for right-to-left strings (like strings in Hebrew), which means the generated mailing labels have Hebrew strings reversed (i.e., printed char-by-char from left to right).
Unless there's a way to convince UFPDF to work with Hebrew strings, an uglish hack can be doing something like
preg_match_all('/(\d+)?./us', $line, $ar);
$line = join('',array_reverse($ar));
for every line that's Hebrew (or Arabic, or any other right-to-left script) only. Otherwise, something to find right-to-left string boundaries has to be found and only the rtl substring reversed. (Note: In PHP, strrev() does not work for UTF-8 characters.)
Maybe, just maybe, the U+202B (right-to-left embedding) and U+202C (pop directional formatting) or the U+202E (right-to-left override) and U+202D (left-to-right override) Unicode characters can be used for this, but I doubt they would work in UFPDF.
The relevant forum thread is at http://forum.civicrm.org/?topic=886