RTP300, Ekiga and Asterisk

Hi, I have searched the forums and didn’t find my answer, so if I missed it i apologize and if you could just direct me to it I would appreciate it.

I have a vonage RTP300 (ATA) that I have “hacked” (it’s mine, why I have to hack it is beyond me). I have an Ekiga sip address. I have a DID from ipkall. Now what I have would work except no voicemail. So what I want is to set up an Asterisk server on my Ubuntu server that will than communicate with the RTP300 so my normal analog phone can receive the call.

Couple questions, what settings to I put in the RTP300 to communicate with Asterisk and vice versa? Does the RTP300 have to be “behind” the server, or is being on the same network domain ok?

Thanks for any information.