apt-get -- doesn't install dependancies?

Hi again,
I never asked so many questions, but since there's no documentation on kfreebsd...

Here, I just installed it and it RUNS!!! I'm VERY glad it does.
However, the installation process left me with a couple of questions. As I'm planning to write a little HOWTO, I'm trying to find out the solution to these, so that folks could securely follow these steps.

So, it seems apt-get didn't install dependencies, when I tried to install KDE4 with it.

First of all, I didn't install with debian istaller, but from command line using `debootstrap` to install base system, then proceeded with apt-get after chrooting into the base system. The reason for such "cunning" approach was that my DVD-writer failed to write a good DVD several times (so I decided its time had come at last) and I had to install from the ISO image itself, using the GRUB2 "loopback" booting option to boot from ISO image.

So... My strategy was quite simple: I just figured I'd tell apt-get to install a random KDE4 application (I chose lilypond for this), and it will install all the rest of the desktop software as "dependencies". Well, it did install a lot of KDE4 files as dependencies of lilypond, but DIDN'T install any KDE binaries, nor KDM, nor even Xorg itself.
Typing `apt-get -f install` returned the encouraging message, that there was nothing to fix in my install...

Therefore my question: are these not KDE's dependencies any more? Or is my idea of "dependencies" too far from reality? Or have I missed some very important steps to make apt-get think the right way?

Thanks for your help,
Kostya