Hi. I've been trying to create a headphone mix so i can hear reverb and other effects ( like autotune) when im recording but i dont when these effects to be recorded on the track. How can i make it work ?
Im using Sonar professional and have a Behringer x1204USB mixer.
Plz help!

The most elegant and efficient solution is to separate effects from the computer. IOW, use outboard gear instead of trying to employ software equivalents, which doesn't work well for a variety of reasons, mainly excessive latency.
 
Get yourself an inexpensive effects unit such as an Alesis Picoverb, which can be had on eBay or Craigslist for $30. Behringer makes a cheap multi-effects box for around $70, but I've not heard it. These would be inserted into the effects loop on your mixer.
 
Those types of effects don't have pitch correction, though. You'll have to spend a little more money for that. Roland/Boss make a unit (VE-1) that has pitch correction as well as reverb/delay for about $150. The good stuff is even more expensive, $250-600, but you don't need to spend big bucks on an effect that's only ever going to be heard in your headphones.

I have the same mixer and you can create a headphone mix that is separate from the mix going to SONAR. Unfortunately, I am in the process of moving and my mixer is currently packed and will be out of commission for a while until we get into the new house, so I can't look at it and tell you exactly how I did it. However, you can use the built in effects on this mixer to give your headphone mix the reverb you want, while sending a dry recording to the DAW.
 
Wish I could be of more help, but other than hitting the boards occasionally, my music is on hold for a while.