Kubuntu backports incompatible with HWE stack for 12.04.3 LTS?

[Richard Foltyn]

Dear listers,

I am trying to install the updated Raring HWE stack on 12.04 LTS,
following the suggestions in
https://wiki.ubuntu.com/Kernel/LTSEnablementStack

I also have the kubuntu-backports PPA enabled since I want to run KDE 4.11:

$ cat /etc/apt/sources.list.d/kubuntu-backports.list
deb http://ppa.launchpad.net/kubuntu-ppa/backports/ubuntu precise main
deb-src http://ppa.launchpad.net/kubuntu-ppa/backports/ubuntu precise main

However, when I run

apt-get install --install-recommends linux-generic-lts-raring
xserver-xorg-lts-raring libgl1-mesa-glx-lts-raring

I get the result that

The following packages will be REMOVED:
  kde-window-manager kde-workspace ..

which is not what I want. The same happens for the Quantal HWE stack.
Is there a way to install the HWE stack and backported KDE on the same
machine?

Thanks,
Richard