flash version won't take secondary domain's cookie

[PerterPon]

Here is my scenes: my page was in a.test.com, so was uploadify, there is some cookie in a.test.com: a_cookie, and there is another cookie in test.com: 'test_cookie', usually, when I send http request in a.test.com, it will take two cookie: a_cookie, test_cookie, but in uploadify, when I use safari or firefox, it only take a_cookie， will not take test_cookie，it's ok when I use chrome and IE。I test http request with flash, it's ok with all kind of browser. So, I think it only happend in uploadify，do you have same problem?