Posted the documents further in the PR but basically, instead of giving them an address in two different fields like we do for most gateways, we're supposed to separate the name of the street and the house number. I contacted their support asking about it and they said I should also include the apartment number in the houseNumberOrName field which makes it even harder to parse the ActiveMerchant address properly. The consequence of doing this wrong would be invalid AVS results (if I can ever get some out of the test account.)