haha
oh, i'm sorry to tell you this... but...
recording a song in 48Khz on the SBLive is the only way to go.
It says that right in the help files all over the place: since the SBLive internally converts to 48Khz anyway, then it will add quite a bit of lag if you're recording at anything other than 48Khz.
START YOUR RECORDING ALL OVER AGAIN AT 48KHZ, AND THE LAG WILL GO AWAY.
That's about all.
Oh yes, and don't use the DS drivers. MME seem to work better, although DS should theoretically have lower lag, for some reason it says it's emulated on my SBLive...