Yes, but I didn't know exactly what to search for so I had no luck
Ok I think I figured this out:
The problem comes from insufficient permissions.
Here are the correct permissions:
sudo chmod 1333 /Volume/[NAME]/.Trashes
sudo chmod 700 /Volume/[NAME]/.Trashes/[UID]
note:
[NAME] stands for the volume name, if it contains a space make sure to place a \ in front of it or use auto completion with the tab key.
[UID] stands for your user id, usually it should be 501 for the initial main user - you can find it out by going to the system preferences - users - (unlock if locked) - right click the user name - advanced - it's in the topmost field.
if the folder .Trashes or [UID] doesn't exist, create them and then apply the above permissions:
sudo mkdir /Volumes/[NAME]/.Trashes
sudo mkdir /Volumes/[NAME]/.Trashes/[UID] e.g. sudo mkdir /Volumes/Macintosh\ HD/.Trashes/501
And when you are finished (make sure you are not copying files etc. in Finder)
killall Finder (to restart the Finder so it will use the Trash)
PS: I link my Previous Mobile Applications folders on my 2nd drive against the trash now (to save some space by not keeping old versions of iOS Apps):
ln -sfv /Volumes/Seagate\ HDD/.Trashes/501/ /Volumes/Seagate\ HDD/Users/macgeneral/Music/Mobile\ Applications/Previous\ Mobile\ Applications
so every time I update an app in iTunes the old version automatically gets moved to the trash.