Different Exception between 2 layers

Question

Hi to all, I would like to ask if does anyone here encounter the problem when a COM+ library application, specifically Business Object, throws an error and becomes different in Webservice application? actually Webservice will call a method from this COM+. and COM+ will throw an error. We have tried many different kinds of method that generates different kinds of exception but still we were unfortunate. We have also read the article about custom exceptions from Enterprise Services but this one uses a COM+ server application. We are trying to do it in Library Application because it indeed happens once but we cannot reproduce it again. So please, does anyone have an idea how to reproduce this phenomenon? Your reply is highly appreciated. Thanks, Pogi.