>Well, if I use some of those techniques to maintain the state, it would get worst as most of the actual users won't be able to use the WS anymore as they are not using WSE but COM directly. So, by using a COM approach inside .NET, this makes it ok for everyone as they just have to make sure they have SOAPClient30 installed.

I see. However, I'm sure some ".NET die-hards" will not like that because they think COM is "legacy" stuff, and they want to do it all with .NET. Wanna bet a beer? :)