I believe that your problem is to import the unmanaged myHID.dll into VB.NET?
If so, you can download the PInvoker Addin from
www.pinvoker.com. It's a free plugin for Visual Studio that allows you to create PInvoke Calls to unmanaged functions and put them e.g. in a .NET Class to use with your .NET Programs.
To Communicate with HID is fairly simple. While I don't know myHID, the usual approach is:
- Know your VID and PID
- Your HID Wrapper can enumerate all the HID Devices with specified VID and PID on the bus, then select the correct one
- Open the connection
- Send / Receive predefinded HID packages
If you want to use CDC USB Class, the whole thing is even easier. You can use the USB CDC Driver provided by Microchip and register your device as "COM-Port". Then you can communicate as simple as with the serial port

.