When creating a software RAID device the list of file system types does not include an LVM physical volume. This makes it impossible to configure LVM over RAID via system-config-kickstart. RHEL 5 and previous versions of Fedora support a kickstart install with the root filesystem on an LVM volume where the LVM PV was on a software RAID-1, I assume that Fedora 8 has the same anaconda support and merely needs matching support in system-config-kickstart.
That is correct, system-config-kickstart does not currently offer any LVM configurability. kickstart itself does so you can use your files with anaconda to get what you want. However, you can't use s-c-kickstart to create/edit anything involving LVM. *** This bug has been marked as a duplicate of 183445 ***