I can't set the right port/chnnel to capture with KdenLIve

I've set (with tvtime and xawtv) the port to the nr. 3 (S-video), and watch it ok
But kdenlive still to capture always the channel 1 of the card (television) (i think)

I've tried also to capture directlu with ffmpeg:

ffmpeg -f oss -i /dev/dsp -f video4linux2 -s 320x240 -r 25 -i /dev/video1 out.mpg
but nothing change.

How I can tell to kdenlive (and/or ffmpeg) direct to use the right input (S-video) ?