You'll have to read the info on the sites. I know that atleast for BHS, they have some online study materials, although you may have to pay for them, I don't know for sure. Documented teaching time is most likely required, possibly along with videos of you teaching/riding, along with the required in-person testing. If you can't find a centre near you, you may have to be willing to travel.
I know on one of the sites you sent me there is a center in September that does the testing. But on the other sites I do not know. I wouldn't be able to travel because I have school and all this other stuff it be helpful it was in the area.
I will look and see what they have :)