Not tried it, but could you do this using the 'multi-leg' route features in the new version? Plan two routes with same start and end, but different en-route parts. Then when navigating you just select the route you want to follow.

Andy

It would be nice to be able to plan (and show on chart) both a route through and around controlled airspace (or indeed danger area) so that if approval to transit is not received the alternative leg bypassing COS is already planned.

Marcus