A tad more complicate. You need to edit your /etc/apt/preferences and set the alioth source to a high pinning number for all kde* packages.
details here:
http://forum.libranet.com/viewtopic....hlight=kde+3+4
in the preferences section, instead of '*' use 'kd*' and that should do the trick
Note that apt will most likely upgrade a whole bunch of other packages since kde will more than likely require them.