You misunderstand... There never was a clover. A clover is not a Japanese cultural symbol. It is most likely a katabami.
A well reasoned argument by somebody with a pretty good description of the cultural background behind it:
http://www.j-aircraft.com/faq/ki61.htm#Re: Ki-61 I Tony "Clover-leaf"It would take a bit of work and some research to hand-craft the katabami and fill in its shape (the photo does not help).
Further, it is very hard to tell if this aircraft is green or dark "chocolate brown," as both were widespread at the end of the war. The only thing known is that it was not bare metal, and that doesn't help a potential skinner.
As you can see, overall this skin choice is fraught with subjectivity, hand-crafting a symbol that can't really be seen, choosing between 2 very different colors because the picture is black and white, trying to figure out any other details (like the yellow lightning bolt through the kill shapes).
That it existed is not in doubt. What it actually looked like, nobody can say.
EDIT: I've run across a comment or two that there exists only the 1 photograph of it, and I haven't turned up anything else other than "artwork" interpretations other than the photo you've shown.
It's been a bit of a debate for years in model-building circles.