Hello,
here is my suggestion that you had better to add
k3b and related packages in a repository:
/scientific/304/i386/apt-rpm/RPMS.contrib

k3b-0.11.17-2.i386.rpmK3b
cdrdao-1.1.7-7.i386.rpm
lame-3.96.1-1.1.el3.dag.i386.rpm
libidn-0.4.6-1.1.el3.dag.i386.rpm

As for SL 303, the above packages already exist in
/scientific/304/i386/apt-rpm/RPMS.contrib

Regards.