So, my way to go around this was to create an image, as so:
var/image/I = new/image('powerobjs.dmi', icon_state = "powbar[powerlevel]")
And after that, I add it to my output, like this:
output += "[I]"
However, it doesn't appear in the interface, I tried both icon and image. But I just can't get it to show. Is it impossible or am I overlooking something?
Thanks in advance.