Features don't update after external edits on featureservice while loaded in viewer

I have a question about updating features that are loaded in the flexviewer from a featureservice.

The service is externaly eddited from desktop and mobile applications. Once the featurelayer is loaded in flexviewer, it only shows newly added features from external edits but no updates or removals. Only on refreshing the entire viewer the changes are visible.

I saw that a autorefresh function is available for dynamic layers but i was wondering if somehow the same could be accomplished on a feature layer. Setting the "mode" option to "onDemand" or "snapshot" makes no difference.

Thanks in advance!