Precisely in that way, very carefully and appropriately, as in The children had to be dressed just so for their aunt's wedding. [Mid-1700s]
I agree, that is correct, as in The house was a mess.Just so; I told her to clean the place up. [Mid-1700s]
See just as, def. 2.
See as long as, def. 3.
Dictionary.com presents 366 FAQs, incorporating some of the frequently asked questions from the past with newer queries.