Hi Umberto,
Currently Cfwdall is only supported for Line 1 on the phone. The only method available to Cfwdall Line 2 etc. is to do it from ccmadmin or the ccmuser web access page.
There is also a third party product called;
IPPhone callForwarder
This new version brings to the user the ability of defining and setting the call forwards from the IP Phone. When selecting the IP Phone callForwarder service, a menu with all available lines will appear. After selecting the line the user wishes to set the forward on, a new menu containing the forward definitions will show on screen. Only those forwarding parameters definied by the Administrator will be displayed. These parameters will show the actual forward destination. The user can then set any of these callForwards.
From this good link;
http://www.myvoipsource.org/index.php?option=com_content&task=view&id=47&Itemid=85
There is a feature/bug request open for this problem CSCdr03425 (Thanks Neeraj!). This bug is still outstanding:(
Hope this helps!
Rob