This tut should work fine except I dont think you need to do this.
"How to install custom ROM (With full wipe)
Download your favorite flavor of rom (I prefer JACHero http://forum.xda-developers.com/showthread.php?t=522076
) and rename to update.zip
1.) Turn on the phone holding the home key and power to boot. Attach the phone to your computer via usb.
2.) Wipe your phone from the menu in cyanogen
3.) Open console and enter the following commands. Press "Enter" after each line. This wipes the ext partition.
mount -o rw /dev/block/mmcblk0p2 /system/sd
rm -r /system/sd/*
4.) Mount the phone so you can copy update.zip over easily by entering the following commands. Press "Enter" after each line.
echo /dev/block/mmcblk0 > /sys/devices/platform/usb_mass_storage/lun0/file
5.) Type recovery to go back to the recovery menu."
6.) Apply the update.zip file then reboot the phone.
maybe thats for the purpose of putting on the hero based roms. I dont remember having to ever do that step .