this MIGHT work but dont curse me if it doesnt.
i dont know your particular yam kbd but if it has l + r stereo analogue rca outputs for example , couldnt you just play back and record into your pc sound card line inputs ?
try audacity - a nice free editor . you could record on pc using audacity.
then try hitsquad.com for a freebie cdrw burning program.
i use nero that came with my cdrw (not free).
another idea is find a friend with a midi input on their pc and see if you can record into the pc like that assuming your yam has a midi ouput jack.
but you will then have to find a midi to wav convertor. hitsquad has a couple i remember.
btw - if you ever fancy putting a nice
midi plus audio sequencer on your pc check out powertracks that i use. pgmusic.com. if you dont believe me talk to users on the forum at pg. this way you could use the pc to do all your midi recording AND add vocals and other instruments.
just some ideas.