Sometimes the Byte Order Bitmark is required - as Code Page for files. The Byte Order Bitmark or BOM is a special character that is required at the beginning of a UTF-8 file.
The principle is only supported for UTF-8 files, as that's where BOM's are for. An example where a file is opened for output in UTF-8 with Byte Order Bitmark:
OPEN DATASET dset FOR OUTPUT IN TEXT MODE ENCODING UTF-8 WITH BYTE-ORDER MARK.
Note that ENCODING DEFAULT also uses UTF-8, but without marker.
To store your file on the presentation server, you can use function module GUI_DOWNLOAD which has a parameter called WRITE_BOM.
You may want to check out the article on Codepage as well.