Unable to automaticly delete or update old imagecache files with same filename

Hi all,

I have a problem with updating my imagecache files. Some cached images are unable to remove or update. Deleting images in the files/ folder works fine, but the cached images of that file are not deleted as well. I can understand that this is how it goes, and that the cached images are suppost to be overwritten next time. But if i upload a new image with the same name, the old cached images will not be replaced by caches of the newly uploaded images.

I also cannot change the write permissions with Filezilla. My maps and files are all in xxx modus. I guess that's because apache is the 'owner'?

Using a hard refresh or running cron does not help, but flushing the caches manually per type in the imageCache menu does. But i can't expect future users to flush it manually through an admin page.

I am thinking that i can use another token to make every uploaded image unique. Now i use the following for naming my images:

[title].[filefield-extension-original]

I'll try to make it more unique by adding date or something. I guess the problem still remains that old cached images will not be removed and just build up onto the server forever...
I'll try adding the file-ID:

[title]-[field_image_cache-filefield-fid].[filefield-extension-original]

I hope someone can help me out. This issue is driving me crazy.
Cheers,
Danny