Ok, an update on the situation: looks like I'm an idiot -.-
I was doing the hp-setup without being su, so of course it wouldn't change
the system settings :P
Everything seems to be working now.
The problem that remains is the test page, that seems to be a problem with a
lot of HP printers (a quick search revealed dozens of people with the same
problem). I shouldn't nitpick since it was given to me second hand, but
still, it's a stupid thing HP make their stuff like this. I will have to try
to solve this, or else I won't be keeping the printer. Lots of wasted ink and
paper on test pages -.-
So, if anyone here can't seem to install a printer, don't forget to make su
before :P
