Systray2 is always under developpement. That's why you won't find all settings in the help file. For every Litestep core modules, reading the changes.txt is hightly recommended...
For others modules, generaly, it is mentionned in the doc that it can be hook to a box.
Currently, you can put almost everything in a box. If there's no !*lsboxhook, try using *wharfmodule. But some modules still doesn't work right... even when they're supposed to be hook.