# File lib_core/rucy/document.rb, line 595
    def virtual_mount(host, document, path, mask=nil)
      host += ':80' if (host !~ /:\d+$/)
      unless (@virtual_mount_map.include? host) then
        @virtual_mount_map[host] = Hash.new
      end
      _mount(@virtual_mount_map[host], document, path, mask)
    end