Okay, I'll take a stab at it.
Well, if you built it, why can't you add the tech to let them move around in it?
Things like a grid with boot clamps that slide around on a track, make it motorized and there you go, in micro-gravity you wouldn't have too much trouble staying up in place, and if you needed to step off to reach some tech, it also has a built-in tether.
The simplest solution would be timed release clamps based on muscular movement in a suit. Sensors would detect the lifting of the leg and the clamp would release, letting you move the leg into position before it clamps down again. A failsafe could be put in place for complete zero-g or near zero-g environments where the clamp won't release if the other isn't clamped on correctly or at all.
(Sorry, no space jumps for you John Carter)
Other people have given answers
(including you @b.Lorenz) with the micro-grip arms or cleats, and I figured I'd mention it since it just gave me and idea.
Compose the boots of Nano-Tech.
Hear me out here, nano-tech is small enough to be air tight for standard spacewalk boots and if extra is stored in the soles, the soles would grow and mold around irregularities in rock and stone, and as far as I know, metals would still have micro irregularities large enough for the tech to stick to artificial surfaces. If you're worried about the grip strength per square inch of surface area on artificial materials, the tech can grow out beyond the edge of the boots to make a larger grip surface (think expanding, kinda-magnetic snowshoes.)