How to start XFCE4 in A13 Debian 4GB SD-card image armel (softfloat) with: MONO

[lachini]

Hi,
I'm buy A13_OLinuXino Wifi.
I download A13 Debian 4GB SD-card image armel (softfloat) with: MONO complete.
but i can not run startx for XFCE4 Desktop GUI!
I'm run aptitude and see :
=========================================================
--\ Not Installed Package (34640)
  --- xfce - The Xfce Desktop Environment (82)
=========================================================

in your site -> https://www.olimex.com/wiki/A13-OLinuXino

A13 Debian 4GB SD-card image armel (softfloat) with: MONO complete

Linux Kernel 3.4.67+
XFCE4 desktop environment
Mplayer CLI
GCC 4.6
iceweasel WEB browser
LCD and touchscreen support
GPIO
I2C
SPI
USB WIFI RTL8188CU, Ethernet AX88772B
Audio
apache2
dpkg
git
i2c-tools
perl
vlc
xorg
Scratch
GCC
Python 2.7.3
PyA13 python module with GPIO,I2C,SPI support
OpenCV
mono-complete
Default Login: root/olimex

please help me to run Xfce.