For the fade In , i guess the best is to change the "Attack" value ( midi control 73 by default )

With VITA VST, or DN e1 it works directly with control channel 73

For some other VSTS , you will need to right click in the GUI of the VST where there is an "attack controller"

The attack value is the amount of time where the voume of the sound goes to 0 to the velocity of the note

Select a number .

Go now in the midi editor , at the bottom select the number you have picked in the GUI of VST .

Draw a curve to change the value of the "attack value"

Normally when you will play the midi file , you will see in the GUI the button of attack changing

For the fade out , it s more difficult . If the preset has a "Release" value , you may change it . The "Release" is the amount of time additional played when the note has finished to be pressed

But in some cases , you will need to change the "decay value" too

In the VITA VST , you may with righ click on the windows of the VST , change the minimal value and the manimal value of ( attack/ devay/ sustain, release . ( in other words , you may set up a range , and the informations of the valu in the midi editor will change between this range 0 = minimum range, dor instance 850 milliseconds , 127 = maximum range for instance 2000 milliseconds )

In some VST instruments , i don t know how to do : for instance with the VST "Concert Guitar" , because there is no "attack, decay sustain , release" controllers