AltGr keyboard shortcuts on MacOS? Is there any way to enable Windows-style AltGr symbol shortcuts on Mac OS? I.e., AltGr+V should be mapped to "@", AltGr+F to "[" etc. AltGr being, in this case, the right Option/Alt key.

I am using a Croatian keyboard layout and the current way for entering those symbols is horrible to say the least. I've tried fixing this using KeyRemap4MacBook, but even though the changes are applied, key mappings remain the same.
You might have better luck building a new keyboard layout with Ukelele.