In the PluginDevGuide is a small bug:
The icon files for a plugin need to have the name logo_small.png rather logo_large.png not icon*.png_
There are multiple occurrences. I think you can simply replace “icon_” with “logo_” in the whole document.
I this worth to be files in JIRA?
(I just mentioned this “bug” because it took me 15 minutes to find out why Openfire didn’t accepted my new plugin icon…)