Hi,

I had this exact same problem several months ago and, for the life of me, cannot remember how it was resolved:

Simple Silverlight application using System.ServiceModel.DomainServices stuff.

When hosting the application in IE parameters to methods returning entities work fine but any parameters passed to methods using the Invoke attribute disappear (or at least appear as default values).
This happens on the production server.
It doesn't happen when running from the IDE using IE and the ASP.NET development server.
It doesn't happen when using FireFox to access the production server.
And, most oddly, doesn't happen using the production site and IE when Fiddler is running on the client side.

UPDATE: FWIW, I think this indicates that HTTP GET is working but POST is not....

Any clues ?
TIA
Viv