How annoying can this be?? I followed the instructions in THIS article to no avail. By the way, if you try this, you should just use the terminal instead of dragging folders like the author explains it in the article.
I had to add one extra step, (or maybe it's the only step I needed) which basically modified the permissions on the trash folder of my external FW drive.
1. Open Terminal
2. Change to drive directory (ie. cd /Volumes/FWDrive)
3. Change permissions on Trashes directory (ie. sudo chmod 777 .Trashes/)
Changing to the directory is safer to me than what is suggested in the article. It makes it harder for you to fat finger and delete the root of the drive, which would wipe out all of your files. Hope this helps.
Also, I used 777 because I didn't want to **** around with permissions. However, this opens read/write to the world. If you want to be more secure, you can do change the ownership first and then chmod to 644 or something.
If you're not familiar with chmod/chown, just do a quick search on them. They are common Linux/Unix commands.