QML Video element and Gstreamer options

[bricke]

Hi everyone, I'm trying to show a video on my qml code (qt5), I'm working on a ARM device.

The problem is that if I create a Video tag (QtMultimedia 5.0) with a sample video I cannot see any video playback.
The error I got is:
@(helloworld:927): GStreamer-CRITICAL **: gst_object_ref: assertion `object != NULL' failed

omx_setup error while setting FilterTimestamp
Allocating new output: 1280x720 (x 12)
Error: "The autoaudiosink element is missing."@

And that's true, I've no autoaudiosink on gstreamer, I'm using nvidia proprietary driver so I've got "nv_omx_videosink" and "nv_omx_audiosink".

I can play the video with the following command:
@gst-launch filesrc location=big_buck_bunny.mp4 ! qtdemux name=demux demux.video_00 ! decodebin ! nv_omx_videosink force-aspect-ratio=true demux.audio_00 ! nv_omx_aacdec ! alsasink@

But how can I tell to the Video element to use another sink element other than the auto one?

Thank you.