Today I already had a reply from ASUS regarding my more detailed follow-up of the start-stop downloads in BT.

This was the reply from Ramon Meems:

Hello,

Unfortunately we don't have a solution for you at this moment.
I would like to advice you to keep an eye on the website and check for the latest firmware update.

If you have any questions please let us know.

Best regards,

Asus TSD Team
So, that was pointless. The fact that it doesn't include any bit of technical information, make it sounds like a standard-insert-a-polite-rejection-email

I hope others have more luck