Setting up Jack Audio - can not detect virtual output

[Cranix]

Hello,
I'm using QubesOS 3.2 with default fedora 24 template
for app vms and i'm struggling with getting Jack Audio working.

I have installed packages with both jackdbus and pulseaudio modules for
jack.
I tried to follow tutorial for intergrating pulseaudio and jack
from offitial jackaudio documentation.
When i'm trying to load module via pacmd or pactl i'm getting Load
failed, both duckduckgo and google did not helped much.

Pulseaudio properly detects qubes vchan sink and uses it to output
audio. My problem is that i can not instruct jack audio to send data to
this output.
I tried to look for more documentation of qubes sound architecture but
without sucess.
Alsamixer shows me (in app vm) nonly 'default soundcard'
pavucontrol finds qubes vchan sink.

Before installation of pulseaduio jack modules i was able to launch
jackdbus via jack_control start, it used dummy output,
jack fails to even start without telling me much what is wrong.

I can paste apropiate logs etc, just please tell me what would be
useful.

--
Cranix

[Cranix]

I managed to load snd-aloop kernel module,
then via alsaloop -C hw:0 -P pulse redirect this virtual loopback
to the right place and mocp is able to play mp3 (i have switched to
loopback via alsamixer).

I'm able to launch jackd -r -d alsa -d hw:0
Then i have launched qjackctl and it managed to find hw:0 loopback card.
Then i have launched zynaddsubfx, changed audio output to jack, then
via qjackctl connected zynaddsubfx to system output.
But it i am not able to play anything from zynaddsubfx.
After killing jackd mocp is again able to play music.

So i'm getting close to ability to play sound via jackd but i have
forgotten about something.

Have anybody managed to set up jack on Qubes?
--
Cranix