Then create a condition with the working hours, name it Open.
Then in the VM CLient goto Specific start points select a group and enable queued and still queued
in the queued and still queued action add as first a Test condition and put "open"in it as the condition to test.
Then add two generic actions, connect on to True and one to false.
In the one connected to true you add a open wav file and in the other the closed wav fil or record it in there as the to use prompt.
Leave the connection form the generic actions open to leave the caller in the queue.
In manager ?> group enable queueing and enable announcements.
Done