Running WCF 3.5 app under .NET 4.0 website

I have a 开发者_StackOverflowwebsite that is hosted on IIS6 and set to use .NET 4.0, but I still have a WCF service on the site that is using 3.5. When i browse my svc file, i get the error:

unrecognized attribute 'targetFramework'

and it point to the websites root web.config. I have tried this MSDN article and still get the same error. My site is using a different app pool than my WCF service, and is configured to use 4.0 in the ASP.NET tab of properties. I have also checked and made sure that my WCF service is using 3.5(2.0) in its ASP.NET properties tab.

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IIS6 does not do mixed framework versions well. If you can switch to iis7 or bring both projects to the same .net version that will remedy the problem

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Why don't you run your WCF under 4.0? Most stuff should be compatible.