I found an alternative solution, but I'm not sure what is the easiest way.
What I did was to create a new installation, copy the definition file from original site and rebuild.
Thereafter I used the download kit funcion in Webnodes, selected all of the content except the root node. Then I uploaded it in the new site. I tried to also include the root node, but then I got a culture error that I couldn't solve. After the kit was uploaded I had to set parents to all nodes on the first level under root.
Unfortunately there are a few other disadventages: You need to generate the templates in Webnodes, set new icons, the create date is set to today.