I am trying to design a new caravan unit that looks like a peasant and requires Diplomatic Capital in order to produce.  I wanted it to act like a caravan because it ignores enemy territory and can create roads.  basically I want to design a diplomatic envoy.  I am tring to come up with creative ways to use the diplomatic capital resource.

anyway, the issue is that I can't get it to come up in the training window.  I copied the caravan XML entry from the CoreVehicles.xml file.  I changed the graphics and animation to look like a peasant.  I gave it the same requirements as a caravan, but, it won't show up for training.  however, it does show up in the Hiergamenon entry for the Trading tech which is the pre-requisite and I do have the tech researched.

is there some kind of hard limit in the system that says there can only be one type of caravan active?