Had this problem on a Fortigate 60B & 60C. Static routes did not work as expected.
The static route did not work until the distance was set to 1 which is lower than the 0.0.0.0 default route who has distance 10. Maybe this is not a bug, but intended behaviour. On Netscreen the 0.0.0.0 default route is always the last to be applied and all other static routes go first.
