Yes you can tune midi.....HOWEVER, it's generally done from the GUI of the synth. Some synths allow this and others do not. You have to look around in the synth's GUI to find the tuning function.
Some will allow you to tune from 440 to say 439 whereas others will only allow a complete half step change.
Glad you solved the other issue.... yeah MME is the usual driver for the factory realtec cards.