not that i'm an expert but i did it by pressing the keyboard note i wanted the bend to end up at with the pitchbend wheel already pulled down so releasing it took me to the pitch of the final note. as a guitarist my natural inclination was to press the start note and bend up. so for a whole note bend up to C i'd press Bb and bend up. trouble is i didn't always hit C correctly. it's easier to start with pressing C with the wheel held down and return to the detente position. my pitch bend wheel is spring loaded so there's no problem of getting the movement smooth. then (showing off probably!) a tiny touch of modulation mirrors the finger vibrato a guitarist gets after a bend.

by the way i've always envied guitarists that can do that for real - bend the note then rock the bending finger to produce a vibrato. then i saw jeff beck do it by bending the note up then using the whammy bar on his strat and if its good enough for him...............