I'm hitting another problem rendering the epub3 and mobi versions.
In my main adoc file I added:
:icons: font
:icon-set: fa
in order to use admonition icons. In my document I use `TIP:` which renders nicely into a lightbulb in pdf and html.
In epub and mobi however I see a bitcoin icon:

I checked that in Apple iBooks, Calibre and Kindle (on Mac). The html for the tip in the epub archive is:
<aside class="admonition tip" title="Tip" epub:type="help">
The assorted-icons and fontawesome-icons fonts are included in the archive, however the included fa font doesn't seem to include a lightbulb, the assorted-icons font does.
I'm using `asciidoctor-epub3-1.5.0.alpha.6` with standard styles, no modifications.
I'm sure I'm doing something wrong, just can't seem to find it.
Thanks for your help,
Torsten.