Hi,
try using [XmlInclude(typeof(bla)] on the appropriate WebMethod. This attribute instructs the ASMX engine to include the type description for type bla.

Cheers,
--
Christian Weyer
Microsoft .NET & Service Oriented Architectures

[Microsoft Regional Director, Germany]
[url]http://www.regionaldirectors.de/[/url]

* XML Web Services: [url]http://www.xmlwebservices.cc/[/url]
* Weblog: [url]http://weblogs.asp.net/cweyer/[/url]


> I am hoping to use an abstract base class as a parameter
> for a webmethod.
>
> In the method I then want to determine what sub-type has
> been passed as a parameter.
>
> For example, I have a abstract class 'Address' and
> derived classes 'UKAddress' and 'ForeignAddress'. Is
> there a way to expose UKAddress and ForeignAddress
> through the proxy without creating a fake web method?