bog If this hack fixes visibility of the text, then it is sounds good.
In the other topic we get keyboard height from ANE and at the same time get keyboard height from AIR. Both of them can be a bit wrong sometimes. So if they say 120 and 110 then use a value like 120+10 for keyboard height. Add more value to maximum value. Because text area needs to be above keyboard at least by 1 pixel.
Maybe this is why it did not worked for you, text is still under the keyboard. To test this you can move application up more than needed. For example make text area at start of screen to see if text became visible or not.