In fact, with portage, there is a file wich indicate all the packages which are very unstable.
You will have to comment the following lines in /usr/portage/profiles/package.mask :
=kde-base/kde-3.2.0_beta1
=kde-base/kdeaccessibility-3.2.0_beta1
=kde-base/kdeaddons-3.2.0_beta1
=kde-base/kdeartwork-3.2.0_beta1
=kde-base/kdeedu-3.2.0_beta1
=kde-base/kdelibs-3.2.0_beta1
=kde-base/kdebase-3.2.0_beta1
=kde-base/kdebase-3.2.0_beta1-r1
=kde-base/kdesdk-3.2.0_beta1
=kde-base/kdesdk-3.2.0_beta1-r1
=kde-base/kdegraphics-3.2.0_beta1
=kde-base/kdenetwork-3.2.0_beta1
=kde-base/kdemultimedia-3.2.0_beta1
=kde-base/kdepim-3.2.0_beta1
=kde-base/kdegames-3.2.0_beta1
=kde-base/kdeadmin-3.2.0_beta1
=kde-base/kdetoys-3.2.0_beta1
=kde-base/kdeutils-3.2.0_beta1
=kde-base/kde-i18n-3.2.0_beta1
=kde-base/arts-1.2.0_beta1
=kde-base/arts-1.2.0_beta1-r1