Image control runtime creation issue

Question

I am having problems getting the Image control to actually
display the image I specify in the source property. The Image
control is created in actionscript at runtime based on XML returned
by an HTTPService request. I have a canvas that I want to populate
with Label, Text, Image, LinkButton, etc. controls based on the
contents of the XML file that is read in, so I have to create all
the components on the fly and use something like this:
var newImage:Image = new Image();
newImage.setStyle("source", "images/myImageFile.jpg");
myCanvas.addChild(newImage);
After I get all the newly created components added as
children to the canvas I go back through and do positioning
(something like this):
for each (var child:DisplayObject in myCanvas.getChildren())
//set the y property of each component to the y of the
previous child plus
//the height of the previous child plus 10 px margin
Wherever there is an image in my XML it inserts the 10px
margin for that component, so I know it's creating it and that it
gets added as a child, but for some reason the image is not
displaying and so the height of the component is 0. I even tried
hardcoding the height of each Image control in case the image was
there but it just wasn't sizing right, but it puts in the space
without displaying the image.
What I'm wondering is if there is some method that will force
the Image controls to either load the image or render it. When I
add an Image in mxml and use the exact same source data it displays
just fine, so the file path is correct. I also have the same images
being read in from XML off the HTTPService that are showing up just
fine in a TileList where my itemRenderer component has an image
with the source set to the same path as I'm trying to use in the
runtime-generated Image controls.
Also, as a side question, does anyone know why a lot of the
properties/methods available from mxml specified comonents aren't
available when you create variables of the same type in
actionscript? For example, if I have
<mx:Image id"img"/>
I can go back in actionscript and reference img.source just
fine. On the other hand, if I declare an Image in actionscript,
thus:
private var asImg:Image = new Image();
and then try to refer to the source property like so:
asImg.source
it doesn't show up in the code hinting and it also throws an
error on compile (reference to a possibly undefined property source
for bla bla bla)
Actually, I've noticed that a lot of the properties and
methods of various components aren't available when they are
actionscript rather than mxml. I didn't see much in the
documentation on the difference or what could be done to work
around it.
Thanks much anyone who has input.

Answer 1

Ok, got it.
I figured that since the <mx:Image> renders just fine
and that the ActionScript Image object doesn't that I'd just create
a custom mxml component with Image as the base element and with
nothing else in it. Then I add an instance of my custom image
component in AS whenever the XML specifies one. The layout was a
bit of an issue, but I just added the image dimensions as
attributes in my XML and size the CustomImage component based on
those.
Must be some subtle difference between the mxml and AS Image
classes that isn't documented very well.