I wouldn't think you could transplant a soil plant into DWC very effectively as soil roots are useless in water. The roots in my DWC system look like feathers or pipe cleaners, instead of shoots. You might also have issues with suspension. I start my clones in rockwool and then put them straight into Orchid nets so the roots start growing through straight away. Transplanting from soil into hydro is fine though, I've done it before with great results (soil sux). I'd recommend a perlite/vermiculite medium that will get in-between the roots. With Hydroton you will get big clumps of roots with no separation until they grow out into the medium. Having big clumps of roots together under 6 inches of Hydroton is just asking for root rot. Just wash as much soil as possible from the root ball without doing too much damage before you transplant it. Good luck