Using XRDP and KDE on openSUSE_13.2

Question

I setup a computer with openSuSE 13.2 and KDE. Now I'm trying to access it from Windows PC via RDP. After my first not successful tries ( see : https://forums.opensuse.org/showthread.php/509719-xrdp-on-openSuSE-13-2-login-failed?p=2728400#post2728400 ) now it works with icewm as window manager but I want to use KDE.

Currently I use xrd 0.6.1 from the LTSP-repo ( http://download.opensuse.org/repositories/server:/ltsp/openSUSE_13.2/ )

I installed tightvnc as mentioned in some forums.

The xrdp.ini contains:

[globals]
bitmap_cache=yes 
bitmap_compression=yes
port=3389
crypt_level=low
channel_code=1
max_bpp=24
#black=000000
#grey=d6d3ce
#dark_grey=808080
#blue=08246b
#dark_blue=08246b
#white=ffffff
#red=ff0000
#green=00ff00
#background=626c72

[xrdp1]
name=sesman-Xvnc
lib=libvnc.so
username=ask
password=ask
ip=127.0.0.1
port=-1

and the startwm.sh contains:

SESSIONS="icewm-session startxfce4 startkde gnome-session mate-session startkde "

#start the window manager
wm_start()
{
  for WindowManager in $SESSIONS
  do
    which $WindowManager
    if test $? -eq 0
    then
      echo "Starting $WindowManager"
      $WindowManager
      return 0
    fi
  done
  return 0
}

if I change the SESSION to startkde or mate-session or gnome-session I get the message: connecting to 127.0.0.1 5910 error - problem connection or just a black screen (gnome)

In the logfiles (/var/log/xrdp.log /var/log/xrdp-sesman.log ) nothing unusal appears.

What am I missing here. Some people seems to run it? But how?