Sorry - a bit late but I'm just getting back into SZ!!!

You have probably sorted it all out by now but anyway, here's my 2 cents-worth:-

• Select the style
  Press "record"
  Select "Record/edit current style"
  Select your Style element (e.g. VAR 1/2/3 etc)
  Press the Menu button
  Select "Event Edit"
  At bottom left you will see the track pop-up
  Select "Master" for the track
  Press "Insert" screen button and a new event will be entered (usually defaults to a "Tempo" event
  (NOTE: YOU MUST INSERT A NEW TEMPO EVENT - don't just change the existing one)
  Set the measure/beat location for it and the Tempo value

This works really well - remember that your FILLs will still be at a different tempo - i.e. you may need a specific FILL to bring you in to VAR4
Also, make sure to change all the active CVs in the VAR - e.g. you may change a chord type and suddenly switch to another tempo


Cheers

Pete