Update.

Well I dragged the SMS-1 to my old PC and ran a RS232 to RS232 connection.

Worked like a charm.

First did the Outlaw update to 2.1.3. Then did the Velo update to 2.1.4. Menu shows that version is installed and can now select a lower-than-15Hz crossover.

So to answer smithy's question: in my experience the answer is no, you need a straight RS232 serial connection.