Sorry, no, not without a lot of custom development, at any rate.

.NET doesn't generate fault information. I suspect this is partially because
there's no obvious source of the information. For instance, a Java method
must be decorated with a throws() clause listing all possible exceptions it
may throw. I presume that a Java-to-WSDL program would use this information
to generate fault elements in the WSDL.

.NET programs don't have that kind of information available. If you really
need this, and if you have nothing better to do for the next few months, you
might be able to write a piece of code to interface with the process .NET
uses to reflect over your code to create the WSDL. Such a piece of code
could do something like parse the XML  file that results from compilation
with XML comments. It could look for the <exception/> information and might
be able to generate fault elements for you.

Otherwise, you're pretty much out of luck without switching to WCF. WCF
allows you to indicate which faults you want included in the WSDL.