It depends on whether Dialpad has taken over control of the configuration of your OBi phone (locked you out of it), or if "automated configuration" you used simply filled in their credentials and other settings for one of the six (not four) Service Provider slots (SP1 through SP6).
If you added the 1032 to your own OBiTALK web portal account:
https://www.obitalk.com/obinet/pg/obhdevthen, click on the 1032 on that page, and then click on the desired SPx, and it will walk you through configuring your Google Voice number for that line.
Here are my (lengthy but comprehensive) instructions on using GV with an OBi product. The instructions were written for an OBi ATA, not IP phone, but the process is essentially the same:
http://www.obitalk.com/forum/index.php?topic=8560.msg56460#msg56460If, on the other hand, Dialpad has taken over your IP phone and locked you out, you'd need to ask them for assistance.
Please post a "review" of your experiences with Dialpad after you've used it for a while. It would be helpful for others considering using the service. By the way, Dialpad was founded by the same folks who built Grand Central, which was later sold to Google, and became Google Voice. I expect that Dialpad will offer superior support and features for business-oriented users.