Cambridge Silicon Bluetooth Dongle - Seen but not working

Hi!

I'd like to use a Cambridge Silicon Radio Bluetooth 4.0 Dongle via my Synology NAS on macOS.

I run my licensed server on the NAS and I can see the device in VirtualHere Client.
VirtualHere says that I'm connected, but I can't see the device neither in Bluetooth Explorer nor in macOS system diagnose.

Already tried:
- the "onReset.$VENDOR_ID$.$PRODUCT_ID$=" flag,
- rebooting
- switching the dongle (I have two of the same)
- removing the other dongle from my mac, in case macOS only supports 1 BT dongle

Any idea on what to do?

Best,
Frank