Using Google Voice with Android phone and a SIP appliance (Obi) I just purchased a Galaxy Nexus HSPA+ with Jellybean(4.1), and have an Unlimited account with Straight Talk. I would like to use Google Voice to handle voicemail for the phone.

Currently, I am using my Google Voice account as a SIP provider for my Obi100 internet phone appliance, but I am using the phone's aswering machine rather than GV to handle missed calls, and I have the Google Voice account set up to act as the phone's voicemail (activated through AT&amp;T, which is Straight Talk's SIM provider.)

The problem is, missed calls to the android phone number, not the GV number, triggers the answering machine at home - calls ring to both the Nexus and the Obi100 device! I have "Go straight to voicemail" checked off under advanced options for missed calls, rather than "ring my other phones first."  

Do I need to port the mobile phone number (which I've had for ~10 years) to GV, request a new number from Straight Talk, and use the new Straight Talk number as the "physical phone" for both accounts? Am I missing something in the phone or the GV configuration to make this work as-is?
If you are using your Google Voice for another purpose, such as a SIP service for an ObiHai appliance or as a VOIP system on your PC, you will encounter problems with Voicemail not picking up. You will need to disable Google Voicemail on your phone, create a new Google Voice account, with a new number, and add your Android phone to that account. Then select "use Google voicemail" and follow the instructions for your provider.

(If you use Straight Talk, select either T-Mobile or AT&amp;T as your provider, depending on the SIM you purchased from Straight Talk.)

The number on the new Google Voice account does not need to be used for anything other than voicemail - calls to your cell phone will be forwarded to the GV number after 4 rings, and since there is no VOIP device listening at that number on the new account, voicemail will pick up.

You will need to log into the new account in the Google Voice app, and go through the setup wizard again.