Sorry, but its coded to a strict RAW, same as how Dwarfs and pride issues. I however coded to allow you to proceed with only a soft error and if your TO/opponent allows you to duplicate then that is their/his call.
Heck while we're on the point of RAW the Wild riders steeds have frenzy
Again poor/sloppy GW rule set. I don't even think they play test game these things out. But hey, enough of a rant. "Now go eat your pretzels and beer and drop a few more quid on our latest model." The GW mentality