Web service client without any WSDL

[martin]

Hi MS-gurus,

I have to use (consume as in client side etc) a large set of web services
hosted by different companies. Some of them have WSDL for their services and
some don't, ie in some cases I just get a PDF files explaining the XML
messages to be sent.
Also, later on there might be more companies joining in and we can't
recompile our application every time a new company (with a new service) wants
to join.
All of these web services does the same thing, but the XML tags they accept
are all different.

So basically, I have decided to prepare each request in a generic XML
format, and hten fetch a special XSLT (from a DB or so) that will transform
the message into the proper XML format for the particular company where this
message is to be sent.

What class in the .NET Framework should I use to transmit the customzied XML
to the proper webservice? I certainly can not use the "Add web reference"
function and general a proxy class, I have to use some lower-level mechanism.
Regards,
Martin