Ok, to continue with this matter, I can confirm that any COM+ component can be automatically published as a web-service without the need of the Soap Toolkit on Windows Server 2003 (and I learned it last week, a bit late).

The bad news is that apparently Microsoft decided to quit this really good thing to replace it with WCF. I hate them :_(

https://social.msdn.microsoft.com/Forums/sharepoint/en-US/c37ac0cb-96c7-405e-8acc-64061afa2e5f/com-as-xml-web-services-on-windows-7-uses-soap-setting?forum=windowsgeneraldevelopmentissues

I suppose that nobody have any new info about it...