Synchronisation to External USB Drive

[Mirakoolz]

Hi.

im trying to figure out if the below backup process is achievable;

- Synchronize certain folders from nas TO external USB Drive;
- - - Synchronize the data for as long as the external USB Drive is connected to the nas. Data changes in the defined folders change every 15minutes
- - - auto start the synchronization whenever the same drive is connected to the nas again

the problem im having is that i can achieve only one of the above, but not both together.
Im looking for solution where the only interaction required with the Nas is to plug and unplug the external USB Drive. i.e; No login to web console.



Long Version:
I have a Server which stores Backup Images to the QNAP (full and incremental image backups). Incremental Backup Images are stored to the QNAP every 15minutes during business hours.
My aim is to have the days backup images copied/synchronized to an External USB Drive which will be taken offsite at the end of each business day.
The next morning, i wish to connect the drive to the NAS for the above process to run automatically, without pressing any buttons or having to log into the web console to 'start' the synchronisation process

what I've tried:
Using Backup Station. Created a backup job to synchronize the folders needed throughout the day. Use the REAL TIME parameter to sync all changes throughout the day
- - It works great the first time. however when reconnecting the drive to the nas, the Backup Job doesnt automatically start the synchronisation. must log back into the web console to start the synchronisation

Using Backup Station. Created a backup job to synchronize the folders needed. Use the AUTO-BACKUP parameter.
- - The Backup Job detects the drive and auto-starts the synchronization process. however, synchronization doesn't appear to continue throughout the day whilst the external usb drive is connected

Using One-Touch USB Copy
- - With the Backup Method set to Synchronize can someone tell me if it will perform a one-time sync or continual sync?


thank you all