You can but it won't do what you think - when you do a send and include an account label this label is then put into the tx - whether the addresses chosen to be used have a "label" (which looks the same as an account unfortunately) on them is irrelevant.

The getaccount and setaccount commands are actually rather unintuitive as they are only having any affect on the "receive" transactions when you issue a listtransactions command.

As far as I can tell the way that it is working is that your outgoing tx's have the account label included when stored in your wallet but as this is not possible for the incoming ones the setaccount and getaccount commands provide a mapping from an address to an account label and it is this map that is used to work out the "receive" tx's "account".