Hi @ipazin,
Something is not right with this continental extension. After i have tried again how you explained i was able to install vernalis extension. but with continental it didnt work. i couldn’t figured out what the problem is. there is an java error which i have posted earlier.
Actually i gave up to use it. 
You have also mentioned this in another post. Continental nodes invisible
we will install soon the new server version ( KNIME Analytics Platform 4.0 and KNIME Server 4.9). i will give it a try.
regards
yasin