mkisofs is broken in RedHat 7.0 beta
(one from RedHat 6.2 is OK)

create a directory yy
 ls -lstr
total 64
   4 drwxr-xr-x    2 root     root         4096 Aug  5 16:42 yy

mkisofs  -r -o cd_image       yy/
Total translation table size: 0
Total rockridge attributes bytes: 169
Total directory bytes: 0
Path table size(bytes): 10
Max brk space used 5024
25 extents written (0 Mb)

works OK, but
mkisofs  -r -o cd_image       aa/=yy/
mkisofs: No such file or directory. Invalid node - aa/=yy/

(which means create aa/ directory on disk and map it to yy/)
DOES NOT WORK.
It was OK in RedHat 6.2