Have you looked at the links you posed? Looks like there's hid modbus usb code in the demojunsimodbushid.zip file that was in one of the links you posted. Bunch of C++ files and some Windows libraries. Is the issue you don't want to run on Windows?
The MemStruct.h file clearly lays out the data.
The demo .zip file looks like it's a Microsoft MFC application.
If you're a bit more clear on what you need help with, I might be able to give you some pointers...