Ubuntu 8.0.4 / Idea 7.0.3 - ALT-GR key DOES NO longer work when i upgraded

Hi everybody,
tryng Idea 7.0.3 on Ubuntu 8.0.4 with an underlyng Jdk 1.6.06.

I can't use the ALT-GR key to type @ # { } and so on (some symbols quite unuseful for a Java Developer :). I have to use a laptop so there's no other choice to type that symbols

Strange is that the key works fine in every other application (as in this post), but the key is NOT recognised in Idea. In Idea I can see the character associated to the key WITHOUT the ALT-GR, as simply it was not pressed

If someone encountered this trouble before, please, help me... I don't want live my remaining life cuttandpasting those symbols from elsewhere.

Thanks