如何在ASP.Net的App_Code文件夹中引用用其他语言编写的代码？

Due to legacy issues I have two folders under App_Code directory. One for VB.Net and another for C#. Problem is, I have a service in the C# folder that needs to leverage a class in the VB.Net folder but they dont seem to know about each other. Any ideas are welcome :)Due to legacy issues I have two folders under A