Howdy Guido,
I would love to help you with this.
I am not sure if Nico understood the client in the other topic, because iCal is an event creation format, not a syncing one. It contains no info about deleted events. So when you delete an event from the source, you can not expect it to get deleted anywhere else. This is the nature of iCal.
The only available solution is to delete the event from the other areas the same time you delete an event from the source.
There is however one feature request we have that you might be interested: Option to remove events not present in a reimported <mark>iCal</mark> feed. The devil is in the details there. In order for the above feature request to help you your source, wherever your iCal file is exporting from, will have to export the entire feed. Typically sources will export all upcoming events, or will only export up to a certain number of events such as 1000. This means that any event over the 1000 mark would get deleted. Further a lot of servers are not powerful enough to import large feeds all at once, so you might even need a faster/more expensive server. I would love to see us implement that feature and some point in the future, but for now it is getting less than 1 vote per month which is far too low to ever get implemented.
Please let me know if you have any questions. Cheers!
– Brook