This may not exactly be the answer you are looking for, but a method to make available the folder in the Unity bar is as follows:
If you add the link to
Nautilus bookmarks, then its available via
Nautilus, i.e, in the list you see on right-clicking the
home icon that you can find in the unity sidebar.
Check this method:
link.desktop file with the following contents:
<path_to_your_folder> with actual path to the folder you need. e.g
Now drag this file onto Unity launcher and see.
N.B: I'm now in Ubuntu 10.04, so I can't check it.