need help with datamapper orm and nestedsets

[eluser]kev[/eluser]
I managed to apply this to an unorder list. see below

Code:

First Category
    First Sub Level

My question is, what code should I need if I want to keep insert childs? I want something like below:

Code:

First Category
    First Sub Level
        Another Sub Level
             Another Sub level again

I'm having a hard time with this.

And by the way, the root id always remain 1. Is that normal?

Thanks