Wow déjà vu. So gnome-vfs is still brain dead. Of course NFS4 is going to be used at some point for home directories and need trash support. Why is the list of supported filesystems still hard-coded in a c file?
Follow the instructions from the previous post, modify them to say nfs4 instead of fuse.
Patch file you can apply to the SRPM of gnome-vfs: gnome-vfs-2162-nfs4-trash.patch