sieve - editheader - edit in place

[Hajo Locke]

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