Is there a better way to call .net 4.0 code from a IIS hosted .net 2.0 application than COM?

I would like to call a .net 4.0 dll from an IIS7 application that is running in a .net 2.0 app pool. I've been researching this and everything I've found so far either said it wasn't possible, or you had to use COM. I have a prototype that uses COM to call the 4.0 from the 2.0 and that works, but I was curious if there was a better way?

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In this case it need to be "auto" hosted, by that I mean no additional config real开发者_如何学编程ly required. so WCF and other similar web services are out. Although I realize that COM has to be registered, it's within existing functionality that we're using so it's "free" so to speak.

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You can Create a WCF service and call that, that will give you the option to run the serivce on a remote machine or locally and use the local machine transports that wcf provides (Named pipes)

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Sorry, i assume you can run .net 3.5 as well, that might not be the case.