How can I pass parameter of type HttpContent in web api?

The back story is i have a web api that simply serves as a gateway to invoke external services. The reason is i don't want to expose the real business api to external services. So, in this gateway controller, it simply receives the information from the business api, calls external services and returns the response to the client, which is the business api. In my gateway controller i have a Post action that takes a parameter of type HttpContent, something like this:

[Route("api/test")] public void Test(HttpContent content) { }

but the web api infrastructure doesn't know how to serialize and deserialize HttpContent type. Is there a way to support my scenario? Thanks.