I am also interested in setting up a gateway.
I don't think you are going to get any straight answers about whether a BitShares UIA is a security until ASIC take an interest and make a statement.
There is a reasonable argument that a UIA used solely for moving cash in and out is not a security: it doesn't have any capital-gain or return a dividend, so it's not an investment in any sense.
My sense is ASIC currently consider crypto-currencies to be too much like hard work and are relieved AUSTRAC have been handled the responsibility. That won't change until they are forced to politically (somebody's granma get scammed by an ICO, media scream "ASIC are asleep at the wheel", etc, etc)
But that might take years, and I don't think its reasonable that the the entire industry freeze development until ASIC deign to decide what's allowed and what's not.
The bigger issue now is banks yanking accounts when they discover they are being used for crypto, this is why having multiple separate independent providers is ideal.
The disadvantage is that we will struggle to provide liquidity if we each run separate markets with our own UIAs. Would you consider making a "wholesale" sale of, say, $10k, of your UIA, and then our clients can use a single UIA in a single market?