Try configuring you disks using ASMlib, its quite easy, simple and managed by itself.
i) Add the disks and make it available to the OS. Format the disk using single partition
ii) Install ASMlib driver packages.
iii) Configure it to oracle user and Initiate the asmlib
iv) Mark the disks as asm disks using oracleasm utility
v) List the device using oracleasm to make sure ur disks are marked by asmlib
vi) Start the installation and go easy and simple..