BTW, does anyone know where is the yum package cache? The yum manpage says that I have to run yum clean packages because they are not automatically deleted, but I can't find them!
I thought maybe I could use the downloaded package to force the reinstall.
And again, with debian, this is a piece of cake, you can just say:
apt-get --reinstall --download-only install PACKAGE
and it will download the package to you and leave it in the cache directory.