I`ve patched the kdebase-3.1.2.ebuild with the dropshadow patches from KDE-Look.org (
Just apply the kdebase-dropshadows-3.1.2.patch and put the file kwin-shadow-3.1.2.patch into
Created attachment 13175 [details, diff]
Created attachment 13176 [details, diff]
Take a look at bug #17468, the issues are similar. Maybe in the future we will support it, but not now.
Dead old bug left to close...