Djinnbass users, how do I program a bass drop?

I'm trying to have the bass slide from 12 down to open. I know I need to use the slide cue but I can't seem to get it sounding right. It seems like I should just be able to hit the higher note, then the slide cue, then the low note, with the 2 notes overlapping. It's sort of doing it but it sounds awful. What am I missing?