How do I copy files *to* my Android using MTP [with Dolphin]

Folks,

It's really cool that I can now pull files *off* my galaxy S3 using Dolphin. However, I can't copy files *to* the phone. I have set up the following udev rules in 99-android.rules (which may be completely the wrong thing to do):

SUBSYSTEM=="usb", ATTR{idVendor}=="04e8", ATTR{idProduct}=="6860", MODE="0666"

Does anyone know how to give me permissions to copy data on to the phone please?

Thanks!