I have finally found a solution for my problem described in older post. Today I have found out that you can run Wuala without GUI. To do this you have to call wuala with the following parameter.

wuala -nogui

But only this is not enough. You have to also login to your account, because Wuala won’t auto login in this case. I have created a bash script which runs Wuala and as soon as it is initialized it logs you in.

#!/bin/sh

# Run Wuala with no GUI
wuala -nogui &

# Give Wuala some time to initialize
sleep 30

# Login
wuala login USERNAME PASSWORD

Change USERNAME and PASSWORD with your credentials and save this piece of code to /usr/bin/start-wuala.sh. Make it executable by calling sudo a+x /usr/bin/start-wuala.sh. After that you can put it to Startup Applications. But before you do that, you should setup your synchronization, because when Wuala starts in background you are not able to start another instance. To shutdown existing instance go to terminal and execute wuala shutdown.
You can also check status of the background process on the following address: http://127.0.0.1:33333/.