Pretty much any way of securely attaching the speakers to the stands will require a somewhat-invasive treatment of the speaker. You could bolt the speakers to the stands, but this would require putting holes in the bottom of your speakers (if holes aren't already present). Or you could use something like the tape that's used to attach metal fenders to truck bodies. But that probably will take a layer off whatever the speaker cabinet is made out of if you ever need to remove it from the stand.

I'm not entirely sure you want to bolt them together anyway. Speaker stands like those (and like mine) are not the most stable structures and the same forces which would knock a speaker off a stand likely will topple a speaker bolted to a stand. It's just that much more to fall and damage things on the way down. I don't have kids or pets (yet) which could hit the speaker/stand inadvertantly; if/when that happens, I'll have to figure out how to move the stands out of harm's way so that is less likely to happen. Or go for floor-standing speakers. :-)