How to 'create' the Koto sound??

can somebody please help me....
i am planing on joining some stage performance at my campus...
i mean i'm just going to be the singer...and some friends will help me with the instruments..
and now we're getting confused when it's about the Koto sound...

okay, maybe, we can just ignore it and go all the way without it...
but, i feel so uncomfortable...
i still want the Koto...T___T

do you guys have any suggestion on what should i do to produce that sound of Koto...??
or maybe you can tell me another instrument which can be used as a substitute of Koto....??
please...please...
i really want to sing Utakata perfectly...

Just use a computer and program it. Easy peasy!

whoa, it'll be very nice to have Utakata as one of your songs to perform~ XD

but well, I don't have much to suggest, I suppose, but I also think of any programming you can use on computer to produce the sound~ but if you think of any musical instruments to substitute with, I don't know for sure whether sanshin would be suitable enough since in my opinion both are quite distinct according to my sensei, at Sarinah there's a place we can learn sanshin, but I've never been there~ T__T

Damn, I should have been more active on this forum..
Cuz.. I've played a song on my classical guitar once, and that song was imitating the koto sound..
(But it doesn't sound as bright as a real koto though..)
Anyway, one of the techniques is to put your hand close to the bridge. Or the most prettiest way of imitating the koto sound is using 'fake harmonics'
I hope you know what 'fake harmonics' are, because it's hard for me to explain on the internet (especially in English ^_^v)