Hi Tim,
Thats right, no cast nets and its not just SA, WA is the same. I dont know about other states.
What would you be fishing for in SA that you need live bait for? Mulloway maybe but anything else you wouldnt need a livey. I guess if you had to have them, you could use one of those rigs with a heap of small hooks on it and try to get som small tommy ruff.
While it is legal to keep female blue swimmers in SA I think you will find that most locals return them to the water and only keep the males, at tleast that's how it used to work.
Cheers
Geoff