I do not own an ARDS itself, but my CycloDS Evolution flash cart does support ARDS cheats. For travel, I keep backups of all my DS games on a flash cart since it's easier to keep everything on one cartridge in the DS slot rather than carrying a bunch of tiny game carts with me wherever I go. I've had bad enough luck keeping track of my old GB/GBC and GBA games in the past. Now DS games are even tinier. This way, I can keep my originals tucked away safely at home on my shelf in their respective game cases while limiting the amount of stuff I leave the house with everyday.
Anyway, on to my main point:
I am currently running CycloDS Evolution with the new firmware v1.58 BETA 2 update, which has experimental compatibility with HeartGold and SoulSilver. So far it has worked and I haven't gotten the random game crashes people have been complaining about on various forums online.
I played around with my backup of SoulSilver (US version) while at my college campus today, and I can confirm that pokemon editing for party and box pokemon does work in Pokesav HG/SS 3a by editing the .sav file. I did not need to use the ARDS method. I haven't tried anything else in Pokesav yet. I played around with species/gender/nature/shiny/move sets, various IVs, etc. So far, the pokemon editing has worked just fine for me. I haven't gotten around to playing with money/items/etc, so I can't confirm yet if those work.
I just thought you'd like to know about the editor working for me.