How to prevent that a Boost::Asio timer blocks the return of the io_service::run()?

How to prevent that a Boost::Asio timer blocks the return of the
io_service::run()?

I have the following (minimized) Class handling my server connection:
class AsioServer {
protected:
boost::asio::io_service ioService;
public:
AsioServer() {}
void add_request() {
//Adding async requests to the ioService
}
void timeout() {
//Stop all pedning async operations
ioService.stop();
}
void perform() {
//Set a timer
boost::asio::deadline_timer timer(ioService);
timer.expires_from_now(boost::posix_time::seconds(5));
timer.async_wait(std::bind(&AsioServer::timeout, this));
//Performe all Async operations
ioService.run();
ioService.reset();
}
};
My Problem is that the deadline timer prevents the return of
ioService.run() until it expires. What I want is the the timer is only
called when expering and then canceling the async operations, but not act
as work in the context of the io_service. Are there timers not acting as
work, or another good way dealing with this situation?