I just release version 1.0.1, which contains a fix for a bug that kept meshes from being converted to siding objects when they were rotated certain ways on the z-axis. Hopefully, I will be able to add support for rotation on the x-axis at some point, which would allow tilted walls.
There are also a lot of little enhancements surrounding adding face groups in edit mode when converting meshes to roof objects. Some of these are the addition of CTRL+A to quickly create a new group, better management internally, an Update All button which recalculates the slope and rotation for all groups, and auto renaming when a group is removed.
The internal changes did make it so face groups from previous versions would not work. So if you have an existing roof mesh, then click Delete Roofing, which will return the original mesh, go into edit mode and remove the old face groups and re-add them. This change is a little inconvenient, but internally this will be more stable and flexible.