Single Model Databinding do not work

Hey,

i'm creating a syncadapter and now i wanna to use single-model databinding.

So in my very easy setup i do this:

<Alloy>
    <Model src="KinveyUser" id="kinveyuser" instance="true" />
    <Window id="win" class="container">
        <Label top=20 id="yolo" color="black" text="{$.kinveyuser.first_name}" >
        </Label>
    </Window>
</Alloy>

var test = $.kinveyuser;
test.set("first_name" , "nico");

Help/Tips would be great! (Collection binding works without problem)

Best, Nico