I'm a screen reader user and put together the following example in IE with jaws for windows on how labels and text areas are read. The short summary is by adding a label to a hidden text field you will do more harm then good to a screen reader user since the label will be spoken with out the associated text field.
<html>
<head><title>testing</title></head>
<body>
<form>
<label>This is a useless label since the screen reader won't read the text box</label>
<textarea rows="10" cols="30" style="display:none">
This will not be read by a screen reader
</textarea>
<label>This is a useful label since the screen reader will read it along with the text box</label>
<textarea rows="10" cols="30" >
This will be read by a screen reader
</textarea>
</form>
</body>
</html>
For a discussion of hiding text from screen reader users or making available to screen reader users while hiding it from everyone else see
http://webaim.org/techniques/css/invisiblecontent/#intro
This is an example of how you can still technically meet a standard but create sites with accessibility problems. While using standards helps with accessibility it does not garantee it. I would suggest that you document this as a necessary deviation from the standard. Your other choices are to add labels which will harm screen reader users but technically make the site meet the standard, or rewrite your site to use a different library.