Hello,
configuring All-In-One on Fedora 18 puts these lines in multipath.conf
(at least on ovrt-njghtly for f18 of some days ago)

# RHEV REVISION 0.9
...
defaults {
    polling_interval        5
    getuid_callout          "/lib/udev/scsi_id --whitelisted --device=/dev/%n"
...
device {
    vendor                  "HITACHI"
    product                 "DF.*"
    getuid_callout          "/lib/udev/scsi_id --whitelisted --device=/dev/%n"
...

Actually Fedora 18 has device-mapper-multipath 0.49 without getuid_callout; from changelog:

multipath no longer uses the getuid callout.  It now gets the
      wwid from the udev database or the environment variables

so the two getuid_callouts lines have to be removed for f18

multipath -l gives

Jan 16 00:30:15 | multipath.conf +5, invalid keyword: getuid_callout
Jan 16 00:30:15 | multipath.conf +18, invalid keyword: getuid_callout

I think it has to be considered.

Gianluca