Sorry I think when I first read your first question I was a bit confused, thinking you were asking if URI’s of soundsets on the server change.
Whenever you upload a soundset to the server a URI is automatically generated for it and that address remains static whilst the soundset is on the server. If you then delete the soundset and upload a new version of it the server sees it as a new soundset and assigns a new URI.
We are looking at integrating the Syrinscape Soundset Creator into Syrinscape online in the future and with that you will be able to make adjustments to your soundsets as you need to. To my understanding when that happens your URI should remain the same, so that should fix the problem you are currently having
Sorry for the confusion before!