What I meant to point out, providing these links, was that the problem is not in the code of our controls, but rather in the way "how ASP.NET does it's databinding". As you can see, the problem can be reproduced even without our controls. Unfortunately, as the problem is not in our code, there is not much that we can do about it.
As the problem is only with container controls, you should not have problems using our controls in the EditTemplate, that are not container controls.
the Telerik team