Nginx - File or directory for new virtual hosts

I just found out that you got a option called “File or directory for new virtual hosts” at the Virtualmin Nginx plugin.
But it only works when creating a new nginx site.
You can’t edit or delete it, because then it says that he can’t find the virtualhost in the nginx config file.

I hope this is not a new bug and that people are working on this. Any news yet?