HttpHandler and querystring (es. test.swf?var=1)

[Matt]

Hello,
I wrote an httphandler for swf files to protect my content.
Everything works if the file is "test.swf" for example.
But if I have to pass an argument to the swf file (es. test.swf?var=1)
I get an exception in:
context.Response.WriteFile("test.swf?var=1");

with this code:

context.Response.Buffer = true;
context.Response.Clear();
context.Response.AddHeader("content-disposition", "attachement;
filename=x.swf");
context.Response.ContentType = "application/swf";
context.Response.WriteFile("test.swf?var=1");

How can I use httphandlers and pass arguments to swf?

Thanks!
Mattia