EDIT: shit, didn't even see your edit, thought it was a big sig :/
You'll need Admin rights on the PC to do this.
First of all, turn off Simple file sharing.
In an explorer window, go to Tools -> Folder Options -> View tab -> untick Use Simple file sharing.
Now you just set yourself as the owner of the directory
Right click on the folder -> Properties -> Security tab -> Advanced -> Owner tab -> Select your user -> tick the "Replace owner on subcontainers and folders" box -> Click OK
Then Add yourself with full access to the folder if it doesn't do it automatically.
Voila
