Problem on sending winkey to linux server.

[Magicloud]

Hi,
    I am using 4.1.2 client on windows and 4.1.2 server on linux.
    In my linux desktop, I use winkey (mod4key) for some functions. 
Well, when I used vnc for remote desktop, it seemed that winkey was 
grabbed (no start menu displaying on local windows), but did not work. 
My linux desktop had no response.
    Should I configure something? Or with vnc keymap, winkey is not mod4key?

Thanks.