<ctiRemoteDeviceLineAssociations> is there for <getRemoteDestinationRes> (the other elements are subelements)....it _may_ be by design that this is only visible via read, as there is some odd modeling done with Remote Destinations in the database/AXL.
The AXL Developer Guide has been updated to reflect the above...if you think <ctiRemoteDeviceLineAssociations> should be present for the other operations, I would suggest opening a ticket so we can investigate with AXL engineering.