RSB GStreamer Integration

I grab images from a dc1394 camera which I like to both display on the screen and publish via rsbvideosink (in order to use them with bag-record). Here's the pipeline:
gst-launch-0.10 dc1394src iso-speed=800 ! video/x-raw-bayer, format=gbrg, width=600, height=520, roi_left=340, roi_top=40, vmode=88, framerate=30/1 ! queue ! bayer2rgb ! ffmpegcolorspace ! tee name="splitter" ! queue ! xvimagesink splitter. ! queue ! rsbvideosink scope=/tebra/video/front

Logger output shows that first images are published (always 18), but subsequent images aren't. The display of images also freezes after 18 images. The pipeline doesn't quit, but just stops working properly without any error message.

Using either xvimagesink or rsbvideosink (without using tee) works fine:
gst-launch-0.10 dc1394src iso-speed=800 ! video/x-raw-bayer, format=gbrg, width=600, height=520, roi_left=340, roi_top=40, vmode=88, framerate=30/1 ! queue ! bayer2rgb ! ffmpegcolorspace ! queue ! xvimagesink
gst-launch-0.10 dc1394src iso-speed=800 ! video/x-raw-bayer, format=gbrg, width=600, height=520, roi_left=340, roi_top=40, vmode=88, framerate=30/1 ! queue ! bayer2rgb ! ffmpegcolorspace ! queue ! rsbvideosink scope=/tebra/video/front

Displaying and encoding the video in a single pipeline works fine, too:
gst-launch-0.10 dc1394src iso-speed=800 ! video/x-raw-bayer, format=gbrg, width=600, height=520, roi_left=340, roi_top=40, vmode=88, framerate=30/1 ! queue ! bayer2rgb ! ffmpegcolorspace ! tee name="splitter" ! queue ! xvimagesink splitter. ! queue ! theoraenc bitrate=256 ! oggmux ! filesink location="/media/local/test.ogg"

Hence, the problem might be the conjunction of tee and rsbvideosink, but I am not able to further specify it.