[curt.clifton]

Tasks that have not yet reached their start date are considered to be "remaining" but are not yet "available". So you can use the availability filter to select based on start date. Mostly. The catch is that a task can also be unavailable for a couple of other reasons. I can be unavailable because it is in a sequential project or group and there is an incomplete task before it. It can also be unavailable because it belongs to a context that is on hold.

Does that help you find a solution? If not, can you give a specific example of a project and tasks and show what you want to appear. (Screenshots are helpful here.)