Shared objects update the things they are bound to

Question

Shared objects (my_so) don't seem to be update the things they are bound to
<mx:Button toolTip="{(my_so.data.wantMusic)?'Turns off music':'Turns on music'}"
               id="musicOn"
               icon="{(my_so.data.wantMusic)?imgPlayClass:imgPlayOff}"
               >
When my_so.data.wantMusic changes the icon doesn't change

Answer 1

I've also done the following:
                private var my_so:SharedObject;
maybe I also need to make the   my_so.data bindable as well so that the
following code works as well?
<mx:Button toolTip="{(my_so.data.wantMusic)?'Turns off music':'Turns on
music'}"
               id="musicOn"
               icon="{(my_so.data.wantMusic)?imgPlayClass:imgPlayOff}"
                cornerRadius="9" fillAlphas="[1.0, 1.0]"
fillColors="[#0FEFBD, #7106D5]" width="26">
        <mx:click>
                <![CDATA[
                    my_so=SharedObject.getLocal("mediaCenter");
                    if (my_so.data.wantMusic)
                        stopIntroSound();
                        my_so.data.wantMusic=false;
                        my_so.flush();
                    else
                        playIntroSound();
                        my_so.data.wantMusic=true;
                        my_so.flush();
                ]]>
            </mx:click>
    </mx:Button>
best wishes
Nikos