I have a WCF Service that is published in Windows Azure. I'm developing a cross-platform application that consumes the service and I patterned my code from the given example here: http://docs.xamarin.com/guides/cross-platform/application_fundamentals/web_services/walkthrough_working_with_WCF/
Debugging the WCF project in Visual Studio works fine, even when I test it by referencing the service using the client address indicated in Windows Azure in a Windows Forms. But for the mobile app, working with the hosted WCF service works "half" fine.
The WCF service compiles certain email messages indicated in the input details which will be uploaded to an FTP server. It will return a response of "Received Emails: [compile emails]/[total emails]". If there is nothing to compile based on the details, the response from the service is fine with a message of "Received Emails: 0/0". But if there is something to compile it has an error of "Value cannot be null. Parameter name: value" <- the error was seen by turning on the "includeExceptionDetailInFaults" in the WCF web.config.