Transparent transition from asmx webservice to wcf service

I'm working on a project where I'm replacing an asmx webservice with a wcf service. However, during a transition period, I'd like to have both work for our customers.

So I've achieved this somewhat, however I've run into a wall during some testing. I'm getting the following message:

Test method IntegrationTests.StrictMatchTests.StrictProviderPass threw exception: System.Web.Services.Protocols.SoapHeaderException: The message with Action 'https://secure.mydomain.net/core/myMethod' cannot be processed at the receiver, due to a ContractFilter mismatch at the EndpointDispatcher. This may be because of either a contract mismatch (mismatched Actions between sender and receiver) or a binding/security mismatch between the sender and the receiver. Check that sender and receiver have the same contract and the same binding (including security requirements, e.g. Message, Transport, None)..

I have an asmx file exposed, and I can consume it as a 开发者_如何学JAVAtraditional web service. However, they don't seem to be compatible with the older service. If I consume the new service, it works just fine. But I would like this initial transition to be transparent to the end user, and gradually have them consume the wcf service over time.

Anyone tackle something like this before? If so, can you please point me in the right direction?

Thanks in advance!

I was able to resolve this issue. I found there was a difference between the two data contracts. One of the properties in the data contract had a case difference. Corrected this resolved the issue. I figured this out by getting a copy of the generated service reference for the old service and the new service. I compared the two references side by side and noticed the case difference.

John - thanks for your suggestions above.