The czech UCW layout should contain all accented letters, that are present in
the Czech language and some other accented letters, that are present on the
remining keys. For instance, there are many ways how an 's' can be accented,
but there is only one way in the Czech language, which is ��. So where on the
QWRERTY keyboard would be s, here is ��. In combination with Shift, the keyboard
layout contains the capital forms of the letters, which can be typed also with
CapsLock. 

To the problem: the �� and �� letters can be written only with CapsLock, not with
Shift, even though the layout file defines them correctly.

How to reproduce:
setxkbmap "cz(ucw)" 
CAUTION! If you write the command in the way showed above, you will replace all
your normal letters and will not be able to write a command to revert the
change. Use multiple layouts at once and select a keyboard shortcut to switch
them.