Kex,
Unfortunately I saw your thread too late.
In the beginning, you should have left the kitten alone. The reason why mamma cat not around...could be 1. she went else where to makan. 2. If she was around, she was afraid to approach becos she consider you to be a threat. Therefore, next time, leave it and let nature take it's own course. Mamma cat will surely come back and fed kitty.
My advice on the same situation in the future, please leave it alone. If you want a cat or kitten, go to SPCA and adopt one. Don't take strays. You'll never know where you are getting. (aka Life is like a box of chocolate, you'll never know what you'll get.) You would not be heartless by leaving it alone. You'll be cruel if you take it back and try to rear it, cos without knowing, you might tear up a union of mamma and kitty. Animals in 'parent/child' scenario have this sense and if the litter is being disturb, they'll become bochap....something like that la.
So be good hor next time. Just bochap.
My condolences to Kitty