Possibility to specify Null value and FillCharacter Togheter

 FixedLength Scenario :
Both FillCharacter and NullFormatter settend on a column.

If the property ha e null value, the write method return the value with FillCharacter and not the NullFormatterValue.

Example :
FillCharacter ='0'
Window Size : 4
NullFormatter : [empty]

Result of write : 0000

I would like that write return [empty]

Its that possibile?
Thank you
