here is the steps to add a external tank for waste ink for the R280. I just got one to replace my r220 and had a hard time finding the info on adding the tank.
info can be found here.
t hese instructions have been supplied by a user in the USA... Apparently it's pretty simple.
Remove the waste ink access panel on back left of the printer (when looking from back). The panel is a clip type lock which a small flat screwdriver should open easily.
Locate and detach the hose that connects to the waste ink receptacle (plastic tank towards the front).. You may need to use a small screwdriver to gently ease the hose/tube over the barb holding it in place.
Attach the waste ink kit to the hose/tubing you've just freed and that's it.
If I'm reading this right it seems that this is much the same as the R300 except you actually have a tank of sorts in the printer. At this point you can either leave the access panel open or cut a small hole in the edge so the tube can exit the printer whilst closing the access panel again.
Here is where you can download the program to reset the counter
you will have to input your model and serial number.