[Matroska-general] seeking in .mkv while recording

[bruno1234]

Hi, i try to seek in a .mkv file while it's writing. My reader is MP9. 
It does not work. The MP9 told the file is in used and can't open. 
I try to grab/save from virtual vcr and open the file with MP9. it's still not 
ok. (file in used)
I try to convert and avi and open the .mkv before the convertion ended 
and it does not work. (file in used)
I try to use graph edit from my web cam the the matroska muxer. same problem. 

How can i overcome ? is it possible ?
I test it whith different codec but it should work with any codec !
 
Many thanks.