ATM k3b fail on 4G files. I have to use growisofs for it and it work fine here. It seems 0xFFFFFFFF cheked here src/projects/k3bdataurladdingdialog.cpp:327 Reproducible: Always
Which version is this about? Also emerge --info missing. And what exactly does "should support" mean? What doesn't work for you?
If you mean that you cannot burn files >4GB, see http://bugs.kde.org/show_bug.cgi?id=145626, will be fixed in k3b-1.1, not a Gentoo bug at all. If you mean something else, than you'll need to describe your issue better, as requested above.
Thanks. Closing.
OK, lets resolve this properly then. :)