With FlexTron server web properties are simply stored in memory. Because there is no process pooling there is no need to serialize them to a database. There is actually no real need to use server web properties other than making your code usable within a regular webapp. Client web properties however are still responsible for communicating with your user interface.
The 5-8 hour thing is not something we have heard before, can your solidly reproduce that? If so, can you tell us exactly how?