UPDATE: This article is out dated as the new iLiberty+ revision can download payloads directly in GUI.
iLiberty+ comes with limited payloads, but has included some payload scripts, such payloads with only scripts appear in “Downloadable” tab under “Advanced” page. To make them usable, you have to download the related archive from the URL given (or from a mirror near you) and put it into payload folder.
For example, suppose we want to install BSD Subsystem, we have to download the archive from the following URL:
http://home.cogeco.ca/~nullriver/BSD_Subsystem.zip
Then put the downloaded zip file into payload folder. When you have done, click on “Refresh” button, iLiberty+ will rescan payload folder and load in any ready-to-run payloads. You should see BSD Subsystem in “Available” tab now.
iLiberty+ may also load in payloads made by other people, all you need to do is put both the payload script (.sh file) and the associated archive (normally .zip file) into the payload. For example, to add payload that upgrades bootloader from 3.9 3.9FB to 4.6 (this is not packaged into the Setup), there’re 2 files:
01BL39FBTo46.sh
BL39FBTo46.zip
You need to put both the above two files into the payload, then click “Refresh” button, iLiberty+ should have no problem load it into “Available” tab.
NOTICE: iLiberty+ does not check if the script is correct, it only scans the script header for needed information. So if the script has a correct header but has bugs, you’ll not find it until it’s executed.

2 Comments
How to do this with the LibertyX
@Honeyf
The two files (whatsoever.sh and whatsoever.zip) have to be packed in tar format (use terminal to do this). Then just browse to the tar file and select it.
/martin