Hi,
I also use Sonar (6, haven't yet upgraded as money went on the Appasionata Strings!).
I've just finished doing the music for a film using the new strings and haven't had the problems you describe.
If you email the midi file to....
alistairlockATukonlineDOTcoDOTuk I'll have a look/listen to it [:)]
Regards,
Alistair