Yamaha DTXpress/DTXplorer/DTXtreme

Hello all, I am in need of a little help here. This morning I have 
been trying to record a drum track for a song my friend wrote. The 
song is arranged where there are alternate quiet melodic parts and 
slighty louder more involved parts. What I was trying to do was use 
the "world kit" setting and have a slow steady rythmn for the quiet 
and record it on track one of a song. Then change to a different kit 
and record the gaps I had left in the song on track two. 
   After recording track one on the "world kit" I then set it up to 
record on track two. Only to find it had changed the track one part 
to sound as the second kit I had selected. 
   Is there a way to record one kit on track one, and have a seperate 
kit on track two.
   Any help would be appreciated as I have been pulling my hair out 
all morning.