[SOLVED] M2P, RP 3B+ and AMP2

Hello everybody,
first of all, I love your product. A very nice way to build a controlable multiroom player. But I’ve got still some issues here.

I want a multiroom setup where the server is in the kitchen (and configurated fine already) and a another in the livingroom for music from server’s squeezebox and Kodi from itself.

Setup
Raspberry 3 B+
HifiBerry AMP2
–> bought as a bundle from your shop
M2P licence

Problem 1:
Get passive speakers to work with AMP2. Is there a way to check if Hifiberry’s AMP2 is sending sound to the output (just to make sure it’s not a problem with the speaker), because till now I couldn’t get my speaker to play a sound?

Problem 2:
If Kodi streams to screen via HDMI I still want to hear the sound from the passive speakers.
So I assume I have to change standard output when HDMI is connected in Raspberry settings. But only standard (HDMI), jack and HDMI are available in the drop down menu.
Well, I now assume to disable raspberry’s internal on-board sound. –> If doing so, squeezelite stops working and cannot be re-started.
Do I have to change settings in the extended audioplayer menu?

I already tried several setups, always with the newest image from your homepage and with newest M2P version. Do kernel and package updates help? I sometimes did that but often appear problems when terminal is updating Apache2.
I already got up a working multiroom setup when choosing ’none‘ as Raspberry’s soundcard and put earphones in the RP’s jack plug. That works fine.

But I want to use AMP2’s passive speaker outputs.
Any help welcome!!
Thanks a lot!