1) I don't know what the KDL-46X3100 is. I found it by checking similar models to help another member complaining about the lack of discrete commands in the KDL-52X3100 dataset ([Link: remotecentral.com]).

2) You can ask Harmony support to copy the "SpeakerToggle" command, or do it yourself if you have another learning remote. There is also an unsupported IR Analysis Center "Backdoor" method but heed all the Warnings. You would also need the Pronto hex code. The "Backdoor" method is a "Use at your own risk" and is not for the faint of heart: [Link: remotecentral.com]