Post [Q] How to transfer file using Wifi-Direct, directly to my SD card (External memory)

I have 1.5 GB free space in internal memory and more thank 8 GB of free space in External memory (SD Card).
When some one try to send files (>1.5 GB) using WiFi direct it gives me an error, kind of "Transfer failed, memory space low".
I know this is due to low memory availability in my mobile (Internal memory).
I have searched many forums for a possible reason to work this out. But couldn't find one. Except people say to be a root user.
Can some one say how to transfer files using WiFi direct, directly to my SD card ????