Both traditional and verb-based routing cannot be used in the same ApiController
Original discussion here: http://aspnetwebstack.codeplex.com/workitem/184
ASP.NET Web API 2 now supports attribute routing, which makes it easy to support both action name based and verb based routing on the same controller.
Try it out in our latest preview NuGet packages.
I've written a blog post showing both types of routing working in the same ApiController. It's supported with out-of-the-box WebAPI. http://blog.appliedis.com/2013/03/25/web-api-mixing-traditional-verb-based-routing/