Kubuntu Raring - Kubuntu-firefox-installer blocks the install of Firefox

I tried to install Firefox by Konsole.
"sudo apt-get install firefox"

Then I got this error:
trying to overwrite '/usr/share/applications/firefox.desktop', which is also in package kubuntu-firefox-installer 13.04ubuntu2

Seemingly this error have been reported already back 2 years ago, but it got fixed then.
Now it's bugged again.

- I can't remove kubuntu-firefox-installer
- I can't install firefox
- I can't fix the dependency hell
- APT is totally stuck because of the kubuntu-firefox-installer file.

Basically if you try this, you break your system. (well, it's Beta 2.)

x@xxx:~$ sudo apt-get install -f
Reading package lists... Done
Building dependency tree
Reading state information... Done
Correcting dependencies... Done
The following package was automatically installed and is no longer required:
  libgconf2-4
Use 'apt-get autoremove' to remove it.
The following extra packages will be installed:
  firefox
Suggested packages:
  latex-xft-fonts firefox-gnome-support
The following NEW packages will be installed:
  firefox
0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
14 not fully installed or removed.
Need to get 0 B/24,8 MB of archives.
After this operation, 55,2 MB of additional disk space will be used.
Do you want to continue [Y/n]?
(Reading database ... 122341 files and directories currently installed.)
Unpacking firefox (from .../firefox_20.0+build1-0ubuntu1_amd64.deb) ...
dpkg: error processing /var/cache/apt/archives/firefox_20.0+build1-0ubuntu1_amd64.deb (--unpack):
 trying to overwrite '/usr/share/applications/firefox.desktop', which is also in package kubuntu-firefox-installer 13.04ubuntu2
No apport report written because MaxReports is reached already
                                                              Processing triggers for man-db ...
Processing triggers for desktop-file-utils ...
Processing triggers for gnome-menus ...
Errors were encountered while processing:
 /var/cache/apt/archives/firefox_20.0+build1-0ubuntu1_amd64.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)
x@xxx:~$