hey man, you prolly arent gonna find a specific part number for that...but there is hope...
basically with belts...the part number describes the belt
you have how many "ribs" there are (usually 3 or 4), if its a ribbed belt. if not then i guess they have some way of describing it.
and you have the actual length of the belt. (circumference of it)
your best bet is figuring out how long you need it, by either using a spare belt you got lying around and cut it to size, or even just a peice of string and measuring.
then just go to repco and ask for the specific belt. you may end up having to trial and error a bit untill you get the right one. annoying yes, but its all part of the fun.
i kinda used this method when i had to get a belt for my mates GTR, they didnt have it on the computer, so just had to get how many ribs it had, and the length of it. and they had various lenghts, going up in 5mm increments (ie 4 ribs, 335mm, 340mm, 345mm etc..)
hope this gives you an idea!