I've read articles that explain how to enable Visual Studio 2010 managed extensions to get them working with Microsoft Visual Studio 11 Developer Preview
Running VS2010 Gallery Extensions In VS11, Meet Git Source Control Provider
However I haven't been able to apply the same logic to Resharper. Although it's a managed extension now, it doesn't appear to be packaged in a VSIX file, so I can't follow all the steps in the above mentioned article.