I am having difficulty setting up shared line on my 921. The documentation says it's supported, and there are options in the configuration, but it's not working right. Here is my setup:

SPA-921 running 5.1.8

Broadsoft R14 SP1

The docs say to enable shared line (under the phone tab I assume, docs aren't specific). Then choose the ext tab you want the shared line on. Docs say don't use Ext 1. The problem is thought, that this is the only option available. If I put my shared line config under ext 1, the phone won't register, even though my softswitch says it is.

Any one been successful getting this to work?

Thanks