Trying to add the Isle of Man cycle network routes to OpenStreetMap, I've come across a problem trying to add a self-intersecting one (where the route joins itself again in the centre). JOSM won't seem to let me add two stretches that I need to add in. Does anyone have tips on how to get this working?

The missing section is the A26 from Ballasalla to St Marks: http://www.openstreetmap.org/?relation=192635