I'm not familiar with the 'lace' part, but IME, I can't kill regular Java fern if i try, including in brackish water. I'd give it a go and see what happens.
I've done a little research and most plant supplies agree that the lace java is just a variety of the regular java fern, so it should do as well as the regular stuff in brackish water.
I myself have never had luck with plants in my BW tanks - but if you have, more power to ya.
I have regular java fern in my 1.005 SG tank, and it would be doing better except my figure 8 nips at it. At the point of "nippage", the plant goes black. Un-nipped leaves still look good.