To clarify: So you use UI.Vision to play a sound file, and then want it to wait until the replay has ended?
UIV can not listen to sound, but it can see! => So I think you can make it wait, for example, until the Play button (of the audio replay tool) becomes enabled again. I am sure something changes visually once the replay is done, and UV can use this as a trigger.
Here is how to wait for an image: If {picture} then {do this}