use multiple blocking pad (one for audio, one for video)

[stic at free.fr]

Hi,
I try to use blocking pad probe to block audio and video flow in a pipeline, then to be able to dynamically change elements.
My stream can have audio + video so I use two different blocking pads.
But it seems the audio blocking pad probe is never launched (callback it not called), wheareas the video probe callback has been successfully called.

I launch blocking pad using:
gst_pad_add_probe (audioblockpad, GST_PAD_PROBE_TYPE_BLOCK_DOWNSTREAM, audio_pad_probe_cb, data, NULL);

Any hint on how to manage two blocking pads ? Is there something special to do in such case ?

Thanks for any answer.
Regards.