sout and snapshot

[buxx8020882]

i am doing something like this
1.transcode and save as a file
2. play it while
3.sometimes i can have a snapshot
the command line i write is this : ":sout=#transcode{vcodec=wmv2,vb=4096,scale=1,acodec=mpga,ab=128,channels=2,samplerate=44100}:duplicate{dst=display,dst=std{access=file,mux=ts,dst="+filename+"}}"
but it dosnet work when is have a snapshot? what shou i do