rebuild_tree without functionality?

Hi members,

as I'm trying to change the order of pages in a PDF, I came into this
problem:

--- snip ---

$quelle = PDF::API2->open("test.pdf")
    || die "Konnte Quell-PDF nicht öffnen!\n";

# read it
$p=$quelle->{pages};
@pglist=$p->get_pages;

# shuffle pages
@newpglist=();
while (@pglist>0) { push @newpglist, (pop @pglist); }

# set new stuff
$root_pages=$p->rebuild_tree(@newpglist);
$quelle->{pages}=$root_pages;

--- snap ---

As far as I can see, there's no functionality in rebuild_tree.
The source just takes the argument, and it returns the number of taken
args???

Seems to be really tricky, to properly change order of pages?

Any ideas?