Samsung's implementation makes it "look like" the card is internal space.
This is one of those oft asked questions. You can see it happen when you copy a file to the card and it "appears" in the internal folder too!
I'm trying to save songs on the sd card, but it also automatically saves it in the internal phone memory. Then, when I delete the file in the internal device, it gets deleted in the sd card. How can I save files in the sd card but not waste internal device space?