well, I've solved the problem via another way:

1. chroot to mer in os 2008
2. paste the ubuntu source to mer's /etc/apt/source.list
3. apt-get update
4.
apt-get -t jaunty install libvte9
apt-get install synaptic
apt-get install onboard

5. install what ever you want， for example, lxde
apt-get install lxde