I have a Joomla website that I am working on and I created a simple animated logo using your Sencha Demo. I really love the software by the way. The problem I am having is that everything works perfectly the way I want it to in Google Chrome, however if you go to safari there is a white background behind the animation. I am using and Iframe for the animation placement. That is the only way I could think of to incorporate it into a joomla website.
Here is the site www.norcaind.com/joomla
Did you make sure to set the scene background in Animator to be transparent?
Also, not sure how relevant it is anymore, but there might be some steps to make the iframe have a transparent background e.g.