Remote Selenium with Firefox profile

We managed to execute a Katalon test suite against a remote Selenium node with Firefox (geckodriver). We now need to set a profile property on that Firefox instance. Setting it manually under the user running the test did not help.
Trying to set a firefox_profile Dictionary the way this:
http://forum.katalon.com/discussion/1812/how-to-set-firefox-preferences
describes does not work either (I get a “org.openqa.selenium.InvalidArgumentException: profile is not a string” error).

Any ideas?

Seems to be solved using autoconfig files: