Sorry to say that I've never heard of the adaptor you speak of. And as such, I strongly doubt it will work with Stella. The reason joysticks work is that they're quite similar to ordinary gamepads, which are easy to support. In contrast, paddles are specific to the original 2600 console. There are devices called Stelladaptor and 2600-daptor that allow Stella to work with real paddles, but it does so by having special code that recognizes these devices. I would guess similar code would be needed to work with a 'bliss-box'.
I'm not even sure how this device sends data over the USB port. Does it send analog or digital data? And in what range??
EDIT: I just did a search for 'bliss-box' and came across this message on their main webpage:
Quote
Version 1.0 was intended to support controllers only. This excludes things like guns, paddles, dance pads, multi taps, and robots. Version 2.0 ( not yet released ) , may support these devices.
So I'm not sure that paddle data is even being sent through the device. But even if it is, Stella would probably still need to be updated to work with it.