A Biztalk 2004 riddle - Catching an exception from a web service

So here's what my friend is trying to do:

He has a web service which is throwing and exception, hard coded, so that we can test if BizTalk gets it.

The exception was thrown either as a Soap Exception or as a regular exception (we tried both ways).

In BizTalk we have a try-catch shape, but we get NOTHING when we try raising the message.

Pretty simple, right? Yet there is no documented way on how this should actually work.

 This might be an issue with the way the web service was written? Or it may be an issue with BizTalk? we're not sure.

The WS is dead simple, just for testing.

As a last resort, I'm posting to my blog. Hope someone in blogland can help.