If you scroll down the list you will find the full installation CD for kde:
That is Debian stable, which comes with kde3.5, not with kde4.
If you want kde4 you need to install Debian testing.
The installer of the actual Debian-testing netinstall-iso has got the option to choose an alternate environment
(xfce, lxde or kde).
After the CD has booted choose: <advanced> and then <alternate desktop environment>.
I don't know if the same is valid for the stable installer.
You might consider if you want to install Debian testing instead of stable. It is already frozen and will be the next Debian stable.