Those are two different questions. If I may, I'll try to answer the one in the title.
In QV Desktop, the reload and presentation function are combined in a single application. On PostReload serves mainly as a method to tweak user interface properties and/or selections based on what data got loaded during the previous script execution.
On a server the situation is quite different. Every reload is performed by a headless application called QVB.exe. On PostReload as a trigger becomes moot because there is no user interface to manipulate simply because there is no user interface at all. QVB.exe operates like a black box device: it loads a document, optionally loads additional data, stores the document on disk and ... disappears. Separately and possibly in an entirely different time frame, a server process called QVS.exe may decide to load a document in RAM and display it to an end user in the client of choice. New problem: there now is a user interface, but no reload is happening, so no On PostReload will be triggered.
