Meebo triggers a mixed content warning in IE

Hey all. I've installed the meebo toolbar on our test website and it's working fine generally except that in some versions of IE, on an https page, it generates a mixed content warning. When i render out the page i look at request.protocol and decide whether to add the "https:true" option to the meebo javascript so i'd have thought it would be fine.

I'm looking at what gets loaded by JS in the IE8 developers toolbar and can see the following problem resource loads:

https://s-s开发者_开发问答sl.meebocdn.net/cim/skin_v89_cim_10_3_4/bar.ie8.http.s-ssl.meebocdn.net.css
https://s-ssl.meebocdn.net/cim/skin_v89_cim_10_3_4/bar.ie8.http.s-ssl.meebocdn.net.css

Now i'm not sure what meebo does with these but even though there a reference to an http (rather than https in there) url it also references ssl and is in fact an https request. So, why does this trigger a warning, does anyone know?

Here's what the developer toolbar info window says:

GET /cim/skin_v89_cim_10_3_4/bar.ie8.http.s-ssl.meebocdn.net.css HTTP/1.1
Accept: */*
Referer: https://cim.meebo.com/cim/sandbox.php?lang=en-GB&version=v89_cim_10_3_4&protocol=https%3A&network=millionaireforschools_ri84xu
Accept-Language: en-gb
User-Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1; Trident/4.0; .NET CLR 2.0.50727; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729)
Accept-Encoding: gzip, deflate
Host: s-ssl.meebocdn.net
Connection: Keep-Alive

HTTP/1.1 404 Not Found
Server: EdgePrismSSL
Date: Mon, 08 Nov 2010 17:39:38 GMT
Content-Type: text/html
Connection: keep-alive
Content-Length: 345

As you can see it's a 404 but i don't know if that is due to meebo going wrong or IE going wrong somehow. Any ideas anyone?

cheers, max

I suspect what's going on is that meebo's javascript creates iframes without src attributes. See http://ajaxian.com/archives/ie-frame-bug and similar posts.