In my dealings with ASP and Flash. You can have flash reference parameters from an ASP file like you were loading variables from a text file. I would have the ASP file write the variables being passed to the page with no whitespace at all.

Example output:
&var1=Tom&var2=Smith&var3=abcdefg&end;

Be sure to have in your ASP code the following (below). This will make sure that your text output like the example above doesn't have any HTML headers, whitespace, etc.

<%
Response.ContentType "text/plain; charset=utf-8"
Response.AddHeader "pragma","no-cache"
Response.AddHeader "cache-control","private"
Response.CacheControl = "no-cache"
%>