Starting from version 1.6, UVs are now exported when you export a terrain as a mesh.
To do so, create an "Export mesh" node and link it to a terrain node, enter a valid file name, select eith "Fbx 2016", "Fbx 2014" or "Obj", then click on the "Export now!" button.
The generated file should contain a mesh with correctly set UVs.
Please let us know if you have any issue with this node.
Thanks.