Run cups-config with the latest Firefox rather than native Iceweasel

[rajibando]

Good morning, Mr. Schultz! Hello, friends!
I apologise for my long absence from the forum.
I want to run cupsconfig (for the newer members, start->knoppix->Printer Configuration ) with the latest standalone firefox rather than the older version of iceweasel. I read the script of cupsconfig
The link for "printer configuration" icon points to user/bin/cupsconfig.
I read the file cupsconfig. Links to either x-www-browser or www-browser. The two linked files are links themselves. They lead further to /etc/alternatives/x-www-browser or www-browser.
I have changed the start->preferences-> preferred applications with the browser as Firefox as a user. Didn't help.
While the x-www-browser opens a terminal-based application, the other one tries to open the sytem's default browser Iceweasel. Since firefox is already running iceweasel can't run.
Now, I could change the exec script in cupsconfig.
I would rather want to implement the code for system-wide configuration. I could do sudo libfm-pref-apps. Actually, I have done it with success.
But what is the best way to do it?
Regards