The whitespace module seems not to support this kind of spaces.
Is there any centralized feature to show/hide those things?
The whitespace module does support this, see the variable `whitespace-display-mappings'.
Something like this should do the trick (if not done via M-x customize-variable RET whitespace-display-mappings RET):
(add-to-list
'whitespace-display-mappings
'(space-mark 8203 [?|] [?-]))
You'll have to M-x whitespace-mode after evaluating this to update the buffer display.
Ciau,
Niels.