Flex App doesn't work over HTTPS/SSL when it calls an XML file

We are currently trying to switch our website so that it must be browsed over SSL/HTTPS.  I have a simple flex application on our website that downloads an XML file and displays the information on a graph.  

Unfortunately, the flex application does not work when we load our website from https.  Rather, the flex app doesn't load correctly and there is just a gray box where the application should be. If I load the page over HTTP, the flex application works.  I tried doing the same with a flex application that did not reference any XML and it worked fine with both HTTP and HTTPS.

Within the MXML, I tried to change the reference to the xml file to begin with HTTPS instead of HTTP.  This did not work.  I have been doing a lot of research via Google and it seems like everyone wants to point me towards the cross-domain file.  I placed the file in the root of my directory and I am attaching the code snippet below. (My Domain is firstheartland.com).

Is there any way to test if the cross-domain file is actually working? Does a change to the file require a IIS restart to take effect. I've been stuck on this problem for months and I don't know what else to do.Start Free Trial

1:
2:
3:
4:
5:
6:
7:
8:
9:
10:
11:
12:
13:
14:
15:

Cross Domain File:
<?xml version="1.0">
<!DOCTYPE cross-domain-policy SYSTEM "http://www.adobe.com/xml/dtds/cross-domain-policy.dtd">
<cross-domain-policy>
	<allow-access-from domain="*.firstheartland.com" headers="" secure="true" /> 
</cross-domain-policy>
 
 
Flex Code:
<mx:Application xmlns:fhc="components.*"  xmlns:mx="http://www.adobe.com/2006/mxml" creationComplete="initApp()" layout="absolute">
 
<mx:HTTPService id="prodHTTP" useProxy="false" showBusyCursor="true"
    	url="https://www......" 
    	resultFormat="e4x" result="handleXML(event);"
/>