I understand that you want to know if it is possible to synch the Favorite Channels list between the SlingPlayer Mobile application for the iPad and the web-base SlingPlayer version.
Unfortunately, it is not possible since the web-based SlingPlayer version does not have the Favorite Channels list.
If you want to get the Favorite Channels list on your iPad, I recommend you to install the SlingPlayer software and create the list. This way you will be able to synchronize them through your Sling Account. The following link will provide you with further information.