ok...here is what I do and it has worked well for me over many years.
Create a new Sonar file (Save As) ex: My Project_mx for stems
Create folders of the tracks that are stemmed together.
Individually Solo the folders and bounce to tracks
Make another new file (Save As) ex: My Project_stems
Delete all tracks except the newly created bounced tracks
Go to Process>Apply Effect>Remove Silence-- (be careful not to cut off any soft sounds)
Export an OMF that includes the following:
embed audio
Split Stereo tracks into dual mono
That OMF should import fine into Pro Tools with all your audio stems in the right place. The remove silence will make your OMF file smaller, but is not a necessary step.