Flash still has the ASO file, which is the compiled byte code for your classes. On Windows, you can see the ASO files here:
C:\Documents and Settings\username\Local Settings\Application Data\Adobe\Flash CS4\en\Configuration\Classes\aso
On a Mac, the directory structure is similar in /Users/username/Library/Application Support/
You can remove those files by hand, or in Flash you can select Control->Delete ASO files to remove them.
I think you're misunderstanding the purpose of the method. As the docs: say, allowDomain:
Lets SWF files files in the identified
domains access objects and variables
in the SWF file that contains the
allowDomain() call.
[...]
By calling
Security.allowDomain("siteA.com"),
siteB.swf gives siteA.swf permission
to script it.
So the call you're making lets swf files on www.mydomain.abc script the swf with the call. You're basically saying, "I trust them to use me properly." It does not allow you to do what you're trying to do (load resources from that domain).
It doesn't make sense to let client code simply ask to bypass cross-domain security the way you're requesting. If all you have to do is ask, why even have the rule in the first place?
To do what you want, you could use either a crossdomain.xml file on www.mydomain.abc, or a server-side proxy. Essentially, the crossdomain.xml file would contain a line like:
<allow-access-from domain="www.yourswfdomain.com" />
, where www.yourswfdomain.com is the domain for the swf file. Obviously, this solution requires support from www.mydomain.abc.
Yahoo has information on setting up a server-side proxy. It's targetted towards XMLHttpRequest, but the same principles apply to Flash.
Best Answer
Presuming you are using Flex, Yes you could.
http://www.deitte.com/archives/2006/08/finally_updated.htm