iOS 6 invisible system button

While testing my app (Ti 3.2.1, iOS 7.0.3) for compatibility with iOS 6, I noticed my camera system button wasn't showing properly. It was there, but only visible by its inset shadow. I realized that this is because it's in a Toolbar and iOS 6 toolbars always have a gradient so that buttons will appear inset in the toolbar. Since I just wanted it plain against the white background, I changed the Toolbar to a View. Now I can't see the button at all.

If I remove the backgroundImage: 'none' I had applied to all buttons to remove the weird white button issue, I can see the button there because the white button shape appears. However, the camera icon never appears.

Here is the current state of that section:

<View id="photoToolbar">
    <View layout="horizontal" height="Ti.UI.SIZE" width="Ti.UI.SIZE" left="10">
        <Label id="photoLabel" text="Upload images" />
        <ActivityIndicator id="activityIndicator" />
    </View>
    <Button id="photoButton" onClick="showPhotoOptions" />
</View>

'#photoToolbar': {
    height: Ti.UI.SIZE,
    right: 20,
    tintColor: '#767676',
    top: 10,
    width: Ti.UI.FILL
},
'#photoLabel': {
    color: '#767676'
},
'#activityIndicator': {
    left: 10,
    style: Ti.UI.iPhone.ActivityIndicatorStyle.DARK
},
'#photoButton': {
    color: '#767676',
    right: 10,
    systemButton: Ti.UI.iPhone.SystemButton.CAMERA
}

If I set a background color and a height and width on the button I can see that area, but there is no icon. Setting them to Ti.UI.SIZE has no effect. Shouldn't the height and width be automatic by default?