This could be tricky, but I'll look into it. You may be able to fix it manually for now. I'm not sure exactly how the text needs to be reversed, but give this a try:
1. Create some hebrew karaoke text using the AE script.
2. Twirl open one of the layers Text properties in the Timeline.
3. From the "Animate:" pulldown in the Timeline, choose Scale.
4. Flip the horizontal scale by setting the values to -100, 100.
5. Twirl open the main Transform properties and set Scale to -100,100 too.
6. Check if the word now looks correct, you could try changing the "Anchor Point Grouping" from Word to Character.
7. Select all three properties you just edited, copy them, then select the other layers and do a paste.
Let me know if any of that works. Also can you send me some stuff to help me test it (send to email@example.com
1. I'll need an SSA file with at least one line of Hebrew text timed out.
2. An After Effects project with that same line of text.
3. A JPEG of that AE frame.
4. If possible, some advice on what I need to do to work with Hebrew text on OS X.