Jason,
I can confirm now that the solution is working 
However just a few words of advice for others.
The Edit transaction to clear the collection must be called with an execution rule, that checks the collection size. It cannot be executed on an empty collection !
In my POC I have 86 entries in my Complex Table that I fill into the collection. If I load and cancel repeatedly, the ATE will crash consistently after 4 or 5 attempts.
After repeatedly reloading the collection, the transaction queue will fill up, and the next transmit may take a while to finish, as all entries in the queue must be processed. This is a little annoying since these data are only meant to exist on the client.
Thank you.
Søren Hansen