Relationship between tempo and imported audio

Hi All,
  I am revisiting Sonar after some time using Ableton. In Ableton when I import audio the software warp engine allows the audio to follow any change in tempo of the project. When I import audio (a backing track), the audio does not appear to be related to the tempo, although it does appear to length of the waveform so that the resulting audio will sound the same for this change in tempo. Is this correct (same as Ableton without the warping)
 
Thanks
 
Jonel

I work with midi, and I write down the tempo changes, as well as the key changes, so I can add them in after importing a piece. Or, if I forget, I just go back and open the old piece, and open tempo and key view, and copy them down then. 
 
I believe opening a piece, as opposed to importing, will preserve the tempos, but of course that only works within Cakewalk.