rocking SPEED/MACH transition

I have done a lot of flights with your nice aircraft the last couple of days and I think VNAV performance (among all other things of course :) ) is impressing. There is one issue though: When passing SPD/Mach transition at FL260 (altimeter set at standard 29.92) the V/s indication on the PFD suddenly decreases from about 2000 to 1500, the pitch reduces remarkedly. After a few seconds, V/S increases again to about 2500 and the aircraft continoues climbing to CRZ alt. My question is wether it is possible to smoothen the transition somewhat. (BTW, wind direction and speed is not changing significantly while passing FL260) at SPD/Mach trans altitude I would rather expect a gradual increase of V/S in VNAV.thanks for any suggestions!