Hello!
I installed HPLIP printer drivers, and when i'm launching toolbox (/usr/share/hplip/toolbox) it says "No installed HP device found" and advices to configure it through CUPS web interface.
The printer itself is working fine, i configured it and printed test page with CUPS web interface.
Also /usr/share/hplip/check says that all dependencies are OK.
And /usr/share/hplip/probe -busb is able to find my printer:

Device URI Model
---------------------------------------- ---------------
hp:/usb/deskjet_3600?serial=HU3BM1R0DR6B HP deskjet_3600

I just don't get it! Maybe i'm forgetting something?
Any ideas?

Is
hp:/usb/deskjet_3600?serial=HU3BM1R0DR6B HP deskjet_3600
the URI that you told CUPS to use for this printer? Or is it actually using something like:
usb:/dev/usb/lp0

Of course! Why didn't i think of that?! That was exactly the problem! CUPS front-end offered me that URI together with other choices, but now it was the first time i payed my attention to it.
Thanks seculor! You helped me a lot!

In my case, CUPS cannot see the hp:/usb/psc_1310_series?serial=MY4B3CB3HMO2, even though I can see it with /usr/share/hplip/probe. any ideas?