Did you label the filesystem when you created it? If not, it won't appear under
/dev/disk/by-label as it doesn't have one!
You don't mention which filesystem you're using, so I'll assume
ext3 as that's the default in RHEL 5. You can use
tune2fs to examine the device:
$ sudo tune2fs -l /dev/sda1 | grep name
Filesystem volume name: home
If this says
<none> then you can use
tune2fs again to add a label:
$ sudo tune2fs -L mylabel /dev/sda1
This should populate
You can also use
-L label with
mkfs.ext3 when creating the filesystem.