I can't reply in that thread so I started a new one.
I've never done this so let me ask you this. Why you need to have Fedora core or Mandrake or RPM entries in sources.list file? I mean Debian itself have thousands of packages that it already is pretty complete. Unstable packages are also very recent updated software packages.
Please enlighten me why we need other sources for APT get and what advantages you have for doing it?