[CentOS] centos 6.2 netinstall does not offer "create custom layout" at "Select type of installation " in text mode installation

Tue Mar 27 20:58:56 UTC 2012
Aggelis Aggelis <aggelis at gmail.com>

I want to install centos 6.2 i386 on a pc with the following specs

cpu 1.8 GHz p4
RAM 512 Mbyte
HD:  IDE 20 GByte

i have downloaded netinstall iso and the installer proceeds AUTOMATICALLY
in TEXT MODE  until the point
that i am asked to select the "Type of Installation" where i am presented
with the following options ONLY

1) Use all space
 2)  Replace Existing Linux System
3) Use Free Space

the problem is that whatever i choose the installer auto-partitions the
hard drive which is something that i do not want.

I suspect that due to the low specs of my pc the installer does not enter
graphical mode installation which gives
the "Create Custom Layout Option" in the "Type of Installation" step.

Is this a bug of the installer in text mode and if not is there a
workaround in order to be able to create a custom layout ?