Simply create a symlink to your device..
Assuming your /dev/cdrom (which is a symlink) is pointing to /dev/hdc then:
ln -sf /dev/hdc /dev/dvd
To see where /dev/cdrom is pointing:
ls -l /dev/cdrom
"But Chad, why wouldn't I just symlink to /dev/cdrom?"
Well you could, but it's suggested not to. Symlinks to symlinks is an unwritten no no. However, if you'd like to, it will work.