How to change permissions on a file in subversion?

I accidentally checked a file into subversion with 755 permissions (rwxr-xr-x) instead of 644 (rw-r—r—). Now, every time the file is checked out, it has the wrong permissions.

I can modify the permissions of the file locally (using chmod), but when I try to commit them, subversion does not detect a modification.

Is there anyway to solve this problem with editing .svn files?