I have a small update. I made it work on my DS-211+ messing around with loads of stuff.
This is NOT a guide, but a recap of things as I remember doing them. I worked on it iteratively for more than 3 hours last night. I hope someone more experienced can use it as a basis to make an install package.
Login as root
Download http://download.unity3d.com/asset_serve ... -2.0.1.tgz
and unpack it
set execution right on the install.sh script
run it iteratively and look for missing .so files
(I googled them and found ipkg packages that contained them. Then I downloaded those and fished out the so files. They were copied ti the system and in one case symlinked to another name)
The script crashes on chkconfig in the asset script. Uncomment the lines, and start it manually
The last problem I found that made it snap in place was that bzip2 was not installed, resulting in the initial database configuration was not run on the database. I fixed it by installing bzip2 and making a symlink to it called bunzip2.
I hope it gives some hints.