final ExchangeCredentials credentials = new WebCredentials(
settings.getExchangeUsername(),
settings.getExchangePassword(),
settings.getExchangeDomain());
service = new ExchangeService(ExchangeVersion.valueOf(settings.getExchangeVersion()));
service.setCredentials(credentials);
if (settings.needsExchangeProxy()) {
final WebProxy webProxy = new WebProxy(settings.getExchangeProxyHost(), settings.getExchangeProxyPort());
service.setWebProxy(webProxy);
}