RouteTable.Routes.MapHttpRoute only available in C#, not VB

I'm trying to build a Web API project using Visual Basic on Webforms.

I've noticed that in the global.asax file, RouteTable.Routes.MapHttpRoute is an option which is only available in the C# version of global.asax.  When creating a VB version of the file, only .MapPageRoute is available.

Is HTTP routing only available in a C# project, or is there another way to call this class?