Problems with characters on Czech keyboard

[Vyletal Petr]

Hello,
I cannot send 2 czech characters using the RealVNC nor the 
TightVNC. These are "s with a hook" (shift + 3 on the 
czech keyboard) and "z with a hook" (shift + 6 on the 
czech keyboard).
My configuration:
Vievew: RealVNC 337, RealVNC 4 beta or TightVNC 129
Server: RealVNC 337
Viewer OS: Win98 SE
Server OS: Win2000

Would it be helpful for me to install RealVNC 4 or TighVNC 
server and try it or is it purely the viewer issue ?
Can anybody help?

Thanks a lot.

Petr Vyletal
Prague, Czech Republic