[Gentoo + Firefox] Configuration of JNLP files

I my work, I had a problem with *.jnlp files in firefox. I must save file to drive and open by click by dolphin. I'm very lazy and in my work i hadn't got enought time to cofigure this. I search solution by google searcher and I found a very beat around the bush article when solution is describing by a lot of words. Below I summarize the most important things to do:
1. open in your favourite editor file:

  1.1 Alternative Firefox directories: .firefox or .mozilla-firefox  
2. repleace a variables: NC:path and NC:prettyName in section:
< RDF:Description RDF:about="urn:mimetype:externalApplication:application/x-java-jnlp-file"
                   NC:prettyName="java" />
NC:path="/usr/bin/java" to NC:path="/usr/bin/javaws"

And From:
NC:prettyName="java" to NC:prettyName="javaws"

I know that it can be set in Firefox->Properties->Applications->file JNLP->[application name filed]: /usr/bin/javaws