disableReadonlyStyling, contentEditable

I have the following situation:

xyz<div contentEditable="false">abc</div>def

From the gui, when I select it all and apply some formatting, it breaks at the read only div, e.g.

<strong>xyz</strong><div contentEditable="false">abc</div><strong>def</strong>

when what I want is:

<strong>xyz<div contentEditable="false">abc</div>def</strong>

I read the documentation about disableReadonlyStyling, no matter what I set it to, I get the same results, also with a variety of styling operations (fonts, sizes, colors). From reading the docs/history on this, it seems that this is exactly what is to be supported by read only styling options.

I'm running CKEditor 3.6.2, testing this in FF 10.0.2

Any help would be very much appreciated