Soundfonts in timidity plugin

[Dainius (GreatEmerald)]

I am trying to setup MIDI playback in Amarok, which uses GStreamer
backend. GStreamer in turn uses Timidity to play MIDI files, and it
seems that all of the soundfont configuration goes through Timidity
configuration in /usr/share/timidity/timidity.cfg. Now the default
instrument set (piano+guitar and drums) works fine, but when I attempt
to get Fluid R3 soundfont working, GStreamer refuses to play it, that
is, the whole soundfont is ignored and only the default instrument set
is heard. But if I run Timidity separately, it can play the MIDI files
with the soundfont just fine. Why is that and is there anything that
can be done about it? From what I can tell, the only difference
between the soundfont and the default instruments is that the latter
uses an sf2 file as an input, while the latter uses multiple patch
files for the same purpose...