i create ks.cfg for customize cd on centos 5.2 but post install section it's not working

%post --nochroot
mkdir -p /etc/test/install/
rpm -ivh /mnt/source/CentOS/rar-3.7.0-0.1.beta1.el5.rf.i386.rpm
cp -rf /mnt/source/CentOS/test.tar /etc/test/instal/
tar -xvf /etc/test/install/test.tar


i copy rar-3.7.0-0.1.beta1.el5.rf.i386.rpm file and test.rar file to /CentOS directory on CentOS DVD (ks.cfg include)

i looking in CentOS directory during install OS (Alt+F2) ,i'm see /mnt/source/CentOS it's contain all rpms and rar-3.7.0-0.1.beta1.el5.rf.i386.rpm and test.rar also. but i can't copy it with post install section command (confuse).

hot to resolve
i want to install rar-3.7.0-0.1.beta1.el5.rf.i386.rpm and copy test.rar to /etc/test/install (extract also)

thank you