Export and Import of Category Tree

[Iddeuh]

To my understanding, a category tree in resourcespace consists of hierarchically arranged keywords. 

If you edit a category tree in the "Manage metadata field options" and make a click on "Manage options" you can see a kind of a categorie tree editor. In this editor it is possible to add keywords and define their parent keywords. This way a hierarchical tree structure is being generated. 

Below the tree editor, there are one import and one export button, which are obviously supposed to enable exporting and importing the tree into a text file. And here is what i'm not getting: When I click on export, a text file is generated which always contains only one level of keywords. 

EXAMPLE 

Tree looks like this: 

animal

  |--insect

    |--bee

    |--ant

  |--mammal

    |--dog

      |--dachshund

      |--bull dog

    |--cat

Exported text file looks like this: 

animals

Or depending on chosen level, like this:

insect, mammal

That makes it a very difficult task to import or export complex tree structures. Is this an intentional behavior or just some kind of bug?