xulrunner27 doesn't work with encoding windows-1251

[t-s-r]

Hi!
I'm upgrading my xulrunner based app from 1.9.2 to 27 version. It seems that xulrunner fail to work with encoding windows 1251
in my xul file I put
<?xml version="1.0" encoding="windows-1251"?>
...
<browser src="chrome://myapp/content/test.html">
...
in test.html I have
<meta http-equiv="Content-Type" content="text/html; charset=windows-1251" />
and some non english, non utf8 symbols
When I start xulrunner I see in place of this symbols "?" signs. What can I do?