does IIS 7 treat ASP.NET errors differently than wcf errors?

when ASP.NET throws an application error, IIS shows the 500 HTML error, but when a WCF service th开发者_StackOverflow中文版rows a FaultException (IIS 500), the client gets a proper SOAP fault with error message in it.

Is there any good documentation on this request processing?

This behavior is exactly how SOAP faults works.

Whenever the code within a Web service raises an exception, ASP.NET catches that exception >and transforms it into a SOAP Fault.

See this link for details