NAS/SMB Folder Permissions

I can't seem to create folder's to which I have write access from OSX on my NAS. From OSX, I have tried connecting via SMB/CIFS, and can create a folder in the root and any subdirectory of the NAS, but when I go to manipulate the contents of said folder, finder says that I don't have the necessary permissions. I have to either telnet in to the device, or can easily use any windows PC and give full control to "everyone". If I create a new directory from a windows PC, my Mac and every other PC can read and write to it just fine, except again - any subdirectories created on OSX can not be written to without using a PC to properly set up the permissions.

The NAS is a hard drive attached to an Asus RT-N66U router, and is set up to give everyone read-write access to the drive. All my windows PCs work beautifuly with the NAS, and I've tried everying in this thread https://discussions.apple.com/thread/3196311?start=60&tstart=0 that would seem to apply.

Can anyone help?