You might need to assign keys to "increase salvo quantity" as the handle does not seem to be modeled on the Ju-88
There is a tutorial & discussion about bombing in the Ju-88 here:
http://theairtacticalassaultgroup.co...u-88-Tutorials
and Blackdog_kt wrote a superb post about bombing here which will help you with the distributor modes, etc, here:
http://forum.1cpublishing.eu/showthread.php?p=293192
Hope this helps!