When sending data in Cyrillic from flash to php5, php deletes everything that should have been saved in xml. Why?

Question

PHP

When sending data in Cyrillic from flash to php5, php deletes everything that should have been saved in xml. And when repeating the entire operation only on the English layout, everything works. I took this into account:
$a = new DOMDocument('1.0','cp1251');
here is the php code:

<?php
$file = 'reg.xml';
$a = new DOMDocument('1.0','cp1251');
$name = @$_POST['amp;name'] or $name = '';
$fam = @$_POST['amp;fam'] or $fam = '';
$login = @$_POST['amp;login'] or $login = '';
$mail = @$_POST['amp;mail'] or $mail = '';
$yea = @$_POST['amp;yea'] or $yea = '';
$day = @$_POST['amp;day'] or $day = '';
$mon = @$_POST['amp;mon'] or $mon = '';
$pass = @$_POST['amp;pass'] or $pass = '';
$sex = @$_POST['amp;sex'] or $sex = '';
$photo = @$_POST['amp;photo'] or $photo = '';
if([email protected]$a->load($file))
{
  $adata = $a->appendChild($a->createElement('data'));
}
else
{
  $adata=$a->firstChild;
}
$aitem = $adata->appendChild($a->createElement('item'));
$aitem->setAttribute('login',$login);
$aitem->setAttribute('name',$name);
$aitem->setAttribute('fam',$fam);
$aitem->setAttribute('mail',$mail);
$aitem->setAttribute('yea',$yea);
$aitem->setAttribute('day',$day);
$aitem->setAttribute('mon',$mon);
$aitem->setAttribute('pass',$pass);
$aitem->setAttribute('sex',$sex);
$aitem->setAttribute('photo',$photo);
$a->save($file);
?>

And the xml becomes like this:

<?xml version="1.0" encoding="cp1251"?>
<data>

<data>

Answer 1

encoding must be utf-8