Hello yaakov,
welcome back to the Polycom Community.
The community's VoIP FAQ contains this post here:
Nov 25, 2011 Question: How can I change the functionality of a softkey button / use EFK?
Resolution: Please check => here <=
Option 11 is probably what you are after.
Please ensure to provide some feedback if this reply has helped you so other users can profit from your experience.
Best Regards
Steffen Baier
Polycom Global Services