Hi all,
Stefano
I think what you describe is what I know as blocks.
You create a part or group of parts and add them to a block library
and when used anywhere within your drawing you can alter
the master in the block library and it will update all of them.
At the moment that option is not available in Moi.

Frederick
not sure what's causing your problem but I would suggest you download and
install the Node editor from James thread
http://moi3d.com/forum/messages.php?webtag=MOI&msg=9358.10

Barry