Action Scrip 3. URLRequest for Cyrillic domain in Fire Fox browser?

Question

Adobe Flash

There is a Cyrillic domain in the ".online" zone. Trying to do a URLRequest on a domain url in Fire Fox but getting an exception

[SecurityErrorEvent type="securityError" bubbles=false cancelable=false eventPhase=2 text="Error #2048"]

I found an article on Habré: habrahabr.ru/post/113887
But the problem is that I do not have a Latin domain and the task is to solve it with Cyrillic.
At the root of the domain is crossdomain.xml

<?xml version="1.0" encoding="UTF-8"?>
<cross-domain-policy>
<allow-access-from domain="*"/>
</cross-domain-policy>

I tried to encode the domain in Punycode (as other browsers do), but I get the same error. Any suggestions for something else to try?