I wish it would work like you want. It would save a LOT of hassle.
For now, what I do is exit the provisioning template for the Cisco phone and at the bottom, before </flat-profile> you can add:
<Extension_7_ group="Phone/Line_Key_7">Disabled</Extension_7_>
<Short_Name_7_ group="Phone/Line_Key_7">Dan</Short_Name_7_>
<Share_Call_Appearance_7_ group="Phone/Line_Key_7">private</Share_Call_Appearance_7_>
<Extended_Function_7_ group="Phone/Line_Key_7">fnc=blf+sd;sub=1002@$PROXY;nme=1002</Extended_Function_7_>
Where the 7's are the line key number on the phone.
You can edit the provisioning template and add anything that the Cisco phones understand to it, for a totally customized provision.
Like:
<Default_Ring__1__ group="Ext_1/Call_Feature_Settings">5</Default_Ring__1__>
<Default_Ring__2__ group="Ext_2/Call_Feature_Settings">5</Default_Ring__2__>
<Default_Ring__3__ group="Ext_3/Call_Feature_Settings">5</Default_Ring__3__>
<Default_Ring__4__ group="Ext_4/Call_Feature_Settings">5</Default_Ring__4__>
Hope it works for you!
-Dan