Mike, from what I can determine is that this tractor has a PTO that turns clockwise. Something you should know is that this series tractor has a weak input shaft going into the transmission and only has 13 HP at the PTO so this is not a very heavy duty unit and is more of the size of a large garden tractor.
I am not absolutely sure on the PTO but from what I have seen this might not be the tractor that will fit the needs as you expressed on the Yanmar that you are interested in also.
Since you are interested in a tractor that can be used for bush cutting this tractor maybe not the one you really want. You actually need something that is closer to a 15-18 HP at the PTO and the B7100 will disappoint you. This tractor would be fine for rototilling and blowing snow but that is about all that it is good to do. But to have it brush cut your pasture this is not it.
It did take the better part of today to get the time to research the PTO on this and I am still not sure that I am correct.
In my mind this tractor you got your eyes on is not the tractor a person on a budget would want as the Yanmars are better supported by the better gray market dealers then the Kubota's here in the United States. Our neighbors in Canada seem to have better luck and you can go to
www.orangetractortalks.com for much better information as they specialize in Kubota tractors and Kubota-ZenNoh gray market tractors. At their forums Vic and Mr K are highly knowledgable and can answer your questions in better detail.