[TYPO3] preventing extension from renaming a file upload

[John Nicholas]

I have a fairly simple extension that allows a user to select a file 
from within the fileadmin folder. It then automatically copies to the 
uploads/extension_name folder and if there is another image there with 
the same name it renames it with a _0x.

The way this extension works, I want to keep whatever name is selected. 
How do I make it either overwrite the image in uploads or even better, 
not bother to copy it at all?