That's not exactly what you asked for, but is quite similar and could bring you what you expected:
http://forum.voxalot.com/voxalot-sup...nectivity.html
I don't know the SPA3102, but it has nearly nothing to do if you take a DID of any provider and redirect it to your Voxalot account.
To my knowledge, Voxalot doesn't offer DID directly. But you may be interested/need registration to an external account (from your DID provider) with paid Voxalot accounts.
Again, iNum is a good solution and, I think, will be the (near) future... I use it preferably to gateways which need two steps dialling.
Regards.