I Wish Sonar works like One Man Band 11. 
Can Sonar be a virtual arranger keyboard? And make  auto-accompaniment software,

Band In A Box does exactly that

Good Night for all people in the Sonar's Forum.

I wanna play with real-time accompaniment. 
Like Software One Man Band11.  (   ) 

In the BIAB, I need, first, enter the chords, than he play,
without, fills, intros, endings, etc. 

like a play-back, a backing track. 

Sonar generally will only play back what you record. MIDI or audio.

Band in a Box doesn't do real time accompaniment. It does preset accompaniment in the sense that you have to preset the chords. An arranger keyboard does this in real time, following chords as you play.

Sonar doesn't do either but it can kinda do the first, you just have to play all parts or find midi files to adapt. Sonar Producer comes with a lot of instruments and a good environment for recording and mixing them all together, but it doesn't automatically generate parts based on a chord sequence.