The Sipura SPA-3000 lacks a useful feature available e.g. on the Xten X-Lite softphone: while it can place calls through multiple outbound proxies, it's apparently unable to register on more than one SIP proxy (registrar). Is there any simple piece of free software (simpler than Asterisk, I mean ;-) ) able to register on several SIP proxies and pass the incoming calls to the single SIP account that the Sipura is registered on?
Enzo