C# - Catch ConfigurationErrorsException For Violating MaxRequestLength?

I am limiting file size users can upload to the site from Web.config. As explained here, it should throw a ConfigurationErrorsException if size is not accepted. I tried to catch it from the action method or controller for upload requests but no luck. Connection is resetted and I can't get it to show an error page.

I tried catching it in BeginRequest event but no matter what I do the exception is unhandled.
Here's the code:

protected void Application_BeginRequest(Object sender, EventArgs e)
{
HttpContext context = ((HttpApplication)sender).Context;
try
{
if (context.Request.ContentLength > maxRequestLength)
{
[Code].....

But I still get this:

Maximum request length exceeded.

Description: An unhandled exception occurred during the execution of the current web request. review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.Web.HttpException: Maximum request length exceeded.

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Update:

What method raises the exception anyway? If I read the request it raises exception If I don't read it at all, I get "101 Connection Reset" in browser. What can be done here?