I created a Jar starter, so you can launch any .jar File within the Portable Apps Menu without the jPortable launcher Dialog.
It uses the jPortable runtime, which must be installed.
You just have to create a New Folder for the app, put in the .jar file (additional files of the app too, of course) and put the also the launcher files into the folder.
Within the appname.ini you have to replace
appname.jar with the name of the .jar file.
For those who are interested, i just created a .bat file with
SET /p appname=<appname.ini
start .\..\CommonFiles\Java\bin\Javaw.exe -jar %appname%
in it, and used a bat-to-exe-Converter to create an Executable file (if you do so, you can include an icon for the app).