You can specify any valid single-byte or multibyte character as a null character for a fixed-width target. You can also use a space as a null character.

The null character can be repeating or non-repeating. If the null character is repeating, the Integration Service writes as many null characters as possible into a target column. If you specify a multibyte null character and there are extra bytes left after writing null characters, the Integration Service pads the column with single-byte spaces. If a column is smaller than the multibyte character specified as the null character, the session fails at initialization.