Attach a string to http.response

Hello
I have an httpmodule which gets unhandled exceptions.
 
In this module I do stuff and afterwards I would like to redirect to an error page and attach the exception string that I have generated
 
here is the code I have for the moment (httpmodule)
 
 
xException ex = new xException(HttpContext.Current.Server.GetLastError().GetBaseException());

ex.logConsole();
ex.logDB();


HttpContext.Current.Response.Redirect("Error.aspx");
  
So What I would like to do, it's to attach somehow the ex.ExceptionString (property of my ex object containing the exception as a string) to the response so that I could get it somehow in the page load of my Error.aspx


what is the best way to do this?
 
I've been trying to write the ouputstream but it seems to b ...