If you have spark le working in vst on it's own instrument track, what is the goal? You want your keyboard controller to be an input for spark? Or you are sending spark data from the pads/seq to another drum module? Remember cubase has "all midi inputs" as on option for midi routing on any track, so try that and make sure your channel is on all or omni. Some drum stuff assumes channel 10. So try that, it would allow the keyboard and spark pads to control a midi track with spark le as the output. There is also a device option that lets you define what " all midi inputs" really means, so you can include or hide certain devices or virtual ports. It boggles the mind the number of ways you can route it.
I use spark le with cubase in a few ways, so if you let me know specifically what you want connected to what, I can try to help. I have spark working fine, and I use it with a custom drum map as an input controller for groove agent at the same time. I actually run the spark sequencer with groove agent sounds and it works great. I have a midi keyboard, but I am usually using that for something not related to the drums, usually another vsti synth. however, I once accidentally routed keyboard input to my spark software and i was playing drums by slamming on the keyboard. Not as nice as the spark pads, but some master keyboards have a grid of pads now that you might want to route into spark.
There is also a way to boot up sparkLE hardware in midi control mode, I have yet to try that.