This is one thing that's always bothered me about Fruity Loops.
The only way I can find to do it, and it hasn't changed over the years, is to edit the "events" and draw a shape you hope is right. Now this works fairly well for filter stuff, but for pitch bending it's like a joke.
I like in Modplug tracker, pitch bending is incredibly simple. I place a note, then a note after it, and put "Tone Portamento" on the second note, and I can choose the speed too.
I don't understand why there is nothing that intuitive here. It's a joke having a "pitch bend" function where you can't even see what pitch you're bending to.
I'm mostly using soundfonts here too.
Ideally I'd like to be able to do Vibrato effects too, for example in synth solos, after a large pitch bend usually comes vibrato(by adjusting the mod wheel usually).
There IS the same possibility in FL Studio - placing 1 note before and 1 after and the sound will slide like portamento/pitch bend. But... This works only with internal FL Studio plugins or the ones, issued by Image-Line. Check help - type in "piano roll slide" for search.
For stand-alone instruments you'd have to mess around with conventional event editor, open and compare 2 windows - piano roll and event editor.
Edit pitch bend events for the sequencer channel pitch knob in the right upper corner of the channel window. Yes, this is tricky, but there's all fun!)))
I'd advice to buy MIDI controller with pitch bend wheel or better stick - look through e.g. Novation products - then I record sequence live performance into piano roll, afterwards open pitch knob event editor and only do some smoothing, bit of timing corrections etc. At that you won't have to care about overall time matching, cause the prerecorded pitch bend events are mostly right at their correct position.
In a that way I successfully record very vivid and fast Slayer 2 solo guitar passages, whereas my friends always get confused about when hearing that that was synth sound and not that I've recently learnt guitar technics and haven't recorded live instrument performance.