So, finally my download finished. The upgrade from tde(squeeze) to tde(wheezy) 
almost wenf flawless. There was just one issue:

# apt-get dist-upgrade
The following packages have unmet dependencies:
 kdeartwork-trinity : Depends: kdeartwork-theme-icon-trinity (>= 
4:3.5.13-2debian0~pre10+4~wheezy) but 4:3.5.13-1debian0+ax1~squeeze is 
installed

# apt-get -f install

Took a while, but no further errors occured.

What's left from tde(squeeze):

# apt-show-versions |grep squeeze
libcaldav 4:14.0.0-0debian11+r4+pr2~squeeze newer than version in archive
libcarddav 4:14.0.0-0debian11+r4+pr2~squeeze newer than version in archive

These  I had to gowngrade manually (synaptic, as I don't know the correct 
command line  options :-) )


Now I strart testing, but it looks very good right now. My former errors did 
not reappear.

Nik