Crown on the real, it is not as difficult as everyone is making it seem. What you need is a sound program that is good it editing tracks (such as Sound Forge). Once you have that import the track in(preferably mp3)to Forge and use the looping control to select the part of the beat you want. Copy that selected sample into a new window. Then you can save that and put it in FL.
Once in there place a snare at every second and fourth count. Set the sample to the musical key you want to play it in. Then press play, heighten or lower the tempo as you try to match your beat. When the snares are hitting correctly than make sure the sample is looping tightly.
There it is. FL Stu is a great program if you can learn and harness its small capabilites to their fullest potential then seek to master tweak even the most minute portion of the track.
Remeber its never the instrument.
peace, love, & nappiness
Casper