Fusion fails at making aa surface extrusion when the taper radius is 90.
Fusion changes the length of the extrusion surface based on the taper radius.
I would have to adjust the extrusion direction to + or - values to change the extrusion direction and this should be done via taper.
Take a look at the Alias Draft Surface a basic surface extrude. You define the length and rotation. Done. Easy.
http://knowledge.autodesk.com/support/alias-products/learn-explore/caas/CloudHelp/cloudhelp/2014/ENU...
So Fusion should be able to:
1. Extrude a surface only as long as the given distance
2. Rotate that surface freele along 360 degree