If you alias the Word array as a Byte array, you can just write 1 byte at a time in the loop.
Code:
arraysize  CON 20
Array      VAR WORD[arraysize]

@ByteArray = _Array
ByteArray  VAR BYTE EXT

FOR ArrayPosition = 0 TO (arraysize*2-1)
    WRITE ArrayPosition, ByteArray(ArrayPosition)
NEXT ArrayPosition