Native transfer only offers a handle to a Device Independent Bitmaps (DIB). DIB are not 16bit per channel.
You are better using memory or file transfer.
The order you want to set these items are.
XFERMECH
ICAP_IMAGEFILEFORMAT (if using file)
ICAP_PIXELTYPE
ICAP_BITDEPTH
ICAP_COMPRESSION
Jim Watters