by looking at the map data, the roads seem to be incorrectly tagged. The bottom one has a part that is tagged as one way, where I believe it should be a "two way" road. If you confirm that you should be able to make the route as you're proposing, myself or someone else will fix it right away.
I've not been there but it seems to me that the top one should be tagged as a service road and the bottom one as a two way highway...but this is just an assumption from looking at it from bing/google satellite view...can someone confirm this pls?