Make sure the Yamaha is recieving MIDI back. Slap on a set off headphones attached to it to verify. You might need to set-up the MIDI out port in Home Studio and be certain that it is transmitting on the same channel as the Yamaha is set to recieve (usually channel 1 by default). Also be sure that Home Studio is not disabling the Yamaha when Home Studio launches (Some programs will transmit for whatever reason, a command that disasbles the sound module of any keyboards attached to the computer. This is usually refered to as the "Local" setting on most synths). Be sure "Local" is set to "On", on the Yamaha. After that you should be able to "Record Enable" the track you want to record on (In order to monitor the input during recording, you'll have to enable the meters for live input monitoring).