Forwarding to Voicemail Server

[Tslam]

I want to use Voxalot as an occasional answering machine for my home phone. I figured the only way to do this was to configure my SPA3k ATA to answer the PSTN when I'm out, then forward the caller to Voxalot; or more precisely, to Voxalot's mail server...

Presumably I can't just forward the call to mysip@voxalot.com, because

1) Voxalot sees my ATA is registered and won't divert to voicemail
2) My ATA can't call my number because that creates a loopback, ie calling my own mysip from my own ATA.

Putting my question in simple terms:

a) Can I (my SPA3k) send SIP calls direct to Voxalot's voicemail server?
b) What's the IP address of Voxalot's voicemail server??

Thanks!