Probe doesn't get EOS events

[Pedro Côrte-Real]

Now that I have an almost working file splitting pipeline I need to be
able to do the reverse. So I've setup a basic:

filesrc ! matroskademux ! matroskamux | filesink

The idea is that I can change the filesrc between files and thus
create a concatenated .mkv file. multifilesrc doesn't work for me as
it requires files with a specific naming convention.

The basic pipeline naturally works well with just one file and then I
went and created an event probe on the filesrc's pad to try and
capture EOS and swap files:

  gst_pad_add_probe (pad, GST_PAD_PROBE_TYPE_EVENT_DOWNSTREAM|
                          GST_PAD_PROBE_TYPE_BLOCK,
                     (GstPadProbeCallback) source_event, &fi, NULL);

The problem is that the callback never gets called. I eventually get
the EOS on the bus and finish the program with no errors. What am I
doing wrong? Can't probes be used to capture EOS events?

Pedro