Front wheel hub assembly / bearing question

I am replacing the other front hub assembly on my 95 gt (should've done 'em both at once, I know...). I meant to ask this question on the first replacement, but was in too much of a hurry.
When I removed the grease cap, the nuts that bolt the hub assembly to the spindle are encased by a six-sided cap that itself forms another nut around the original nuts. Last time, I just broke off the cap and worked with the nuts directly. Should I instead try to find a way to work with the cap? I couldn't find a socket anywhere that fit it, though I found a good one for the nuts.
Is it OK to just break off the cap? (this is of course not the grease cap, which I already popped off)

pictures to follow...