RHEL 7.0 GUI installer - howto create custom disk partitions, PVs, VGs and LVs creation ?

Hi,
i'm looking at the installation screen (GUI) of the RHEL 7.0 install and i'm dumbstruck how to create custom layout for the server installation.
How do i create there partiotions, tag them as PV (physical volumes), assign PV to VG (volume groups), custom name them and finally create LVs (logical volumes) with FS (filesystems).

I can't find any customization options like that in need (as said above) in the GUI installer, even after choosing "custom partitions creations" option.

This is really stupid GUI. The Gui installer gets more stupid with every higher release number!

Now, please someone tell me, that it's me who is dumbtool and that i'm missing big red button somewhere in the install process, that will enable me to do all the real sysadmin job like i said in the title.

Thank you