ClickTrack & Finding TEMPO of a mixed song WAV/MP3 Sonar to adjust the bars to clicktrack

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ClickTrack & Finding the TEMPO of a mixed song WAV/MP3 -  Sonar to adjust the bars to clicktrack??

When importing a WAV or MP3 file to use as backing track (instrumental)  to sing over it, which many times we do for someone who just wants to interpret that song or brings me a mixed beat so they can sing over it.  I always went to another software first to find the tempo of the WAV/MP3 file and then apply that tempo in Sonar so that it adjusts the bars accordingly and its easier to work with v-vocal time editing as you could see how the voice of the person being recorded falls at the beginning or ending of the 1/16 bar more or less but its not exact... Also, if you play the CLICK TRACK, it may sound like the tempo I imputed (lets say 109.22)  is about right but it's never exact and the click track can get a little off beat later in the song sometimes right from the beginning, its the right tempo but clicker is a little off or may drift off later in the song.  Considering that another software estimated the tempo and then I manually enter that Tempo number in Sonar.  It works good since you're NOT creating any music at that time but the click track is useful for some people just to sing, especially on ballads that have parts in the music where the beat goes away and only a piano remains or lets say when there is a pause in the music or a long intro and they wanna count how many clicks...  
??  Is there a feature where it finds the tempo of this WAV or MP3 song and adjusts the bars so that the click track follows it exactly and goes with it??   I mean with it being so advanced and all and even audio snap being so impressive and algorithms that can calculate so well... How would I do that in Sonar??  

AudioSnap has the ability to create a tempo map based on a reference track. I have used this on many occasions to add tracks to an existing multitrack recording that had been made somewhere else. 

The catch is that you need a good reference track for it to work reliably, something with clearly-defined beats. In my case I was using a separate kick track, which works wonderfully. I have never attempted to pull this off with a full mix, though. Whether or not it's even possible would, I think, depend on how well-defined the drums are.

Thank you

How do I do it?
Open the Audio Snap Palette SHIFT + A 
select the track and then?  
I'm looking for it to give me the tempo of the mixed song and create a tempo map for it to follow the click-track 
I know it depends on the song and the clarity of its percussive transients but I want to give it a shot, there are people who do this in their studio and I wondered if they used something outside of their daw to obtain this tempo, I know I do.. I use mixmiester to get the tempo bpm number, and its accurate, it somehow finds the transients, but from there to the click track following is hit or miss, but thats because sonar wasnt the one doing it and I was imputing the tempo manually.  Like you said, creating a tempo MAP is exactly what I want, may or may not work but I want to try.