Reviving this thread for the solution I implemented.
In case you hadn't figured this out: OP, if you wanna show your own AND your friendly Druid's HoTs, you have to add 2 buffs each:
One with "Cast By": Friendly, one with cast by Self
I couldnt make it work. Maybe it had something to do with incremental updates.
Anyway, I purged healbot from my system (addon, settings, data) and reinstalled, now its working again, just have to re-setup everything.
Thanks for tryign to help :)