In fact the problem is in two locations:
1. /etc/fstab in rootfs which has /cdrom with iso9660 format and read only -> ext2 rw
2. linuxrc in initrd.gz in isolinux (boot partition), the script goes over the /proc/ide/hd? files and check whether it is a CDROM or not. if so the partition is mounted under /cdrom. Of course it will not see hda2 therefore I forced it by adding a couple bash lines after Fulvio’s. It is crappy but does the job in order to load the hda2 in ext2 format.