Building accessibility into courses with layers and complex interactions

Hello,

I am trying to build a course using Storyline 2.7 that meets 508 accessibility standards. I have been using the Tab Order dialog box, changing the tab order of objects on each slide and adding Alt text. I've been running into problems with slides that have layers and objects with states. The screen readers I'm testing with, NVDA and JAWS, don't read the text objects or the Alt text for graphics and buttons. The tab order works and the reader notes that it has moved ("check") to a new object.

Is it possible to build courses that have a lot of interactivity and are 508 compliant? The Tab Order dialog box lists all the elements from each layer; how do you set the tab order so that it only tabs to elements present on the active layer? Are there any best practices regarding accessibility and interactivity in Storyline courses?

Any ideas are welcome and greatly appreciated.

Thank you