sieve - editheader - edit in place

Hello,

i do some tests with sieve editheader extensions. deleteheader and addheader are working, but i noticed that new headerlines are always prepended to current header. So new lines can be found always on top. I am looking for a possibility to edit a headerline in place, without moving the new line to top of stack(replaceheader?). It is not looking good if a Subject-Line suddenly moves to top of header. Is there a possibility for me?

Thanks, Hajo