Daniel,

WSE Transport infrastructure layout is the same for any kind of transport
(it's abstracted by SoapTransport class). For actively listining channel
(SoapChannelCapabilities property) its GetInputChannel(...) method will
return back the SoapHttpRequestChannel channel for the specific endpoint.
This channel has implementation of the ISoapInputChannel and
ISoapOutputChannel interfaces and reference for the configured formatter
(SoapPlainFormatter).

Activating (plumbing) your service hosted by IIS is done in the web.config
file like is shown in the following example:

<httpHandlers>
       <add verb="*" path="MyService.ashx"
type="NamespaceMyService.MuService, MyServiceAssembly" />
</httpHandlers>

The SoapReceiver has implementation of the IHttpRequest interface which it
enables to process HttpContext in the ProcessRequest method. This method
dispatches incoming HttpContext to the specific endpoint
SoapHttpRequestChannel receiver to deserialize an incoming stream into the
SoapEnvelope message. After that the message is dispatched to your receiver
method via the SoapReceiver.ProcessMessage.

The Level 0 of the WSE2 Messaging infrastructure can be customized building
a Custom SoapTransport and/or SoapFormatter.

Note that the channel's classes (such as SoapHttpRequestChannel,
SoapHttpOutputChanne, etc.) are sealed classes and SoapHttpTransport will
not help as a derived class for your custimizing.

hth

Roman