Problems installing k3b in unstable

[Michelasso <qzerty@gmail.com>]

Hello everybody,
I have this problem with k3b; first time I tried to install it with
apt-get, and I got an error due to missing dependencies:

The following packages have unmet dependencies:
  k3b: Depends: libmusicbrainz4 (>= 2.1.1) but it is not installable
  k3blibs: Depends: libflac++4 but it is not installable

But looking in debian amd64 packages repository I have seen that for
unstable are available the following packages:

libflac++4c2_1.1.1-5.2_amd64.deb       
libmusicbrainz4c2_2.1.1-3.2_amd64.deb

So I thought that maybe they are the replacements for the missing
ones; so i manually downloaded and forced the installation of k3b and
all the packages required with dpkg --force-depends
Now k3b seems to work, but I have problems using apt-get or aptitude
to install other packages: every time I launch them they complain
about the missing dependencies of k3b and k3blibs and apt-get stop
while aptitude wants to remove them.
Is there any way to tell them to keep the packages installed and to
proceed with installation of other packages?