This seemed like a bug to me, and I reported it in 2011! 
It turned in to an FR, and with the inestimable help of @vic_france, in Cubase 7 we got Mirror, which I would call Retrograde. Work continued – MIDI Functions Reverse and Mirror - #4 by steve
I would still like the jargon to match music theory jargon, and call ‘mirror’ retrograde.