Hi martin (and perhaps others who are interested),
after you've installed zumi's ipk's, install the ipk below.
It is a version of the fvwm-xmms-ctrl that honours the keys of the remote
control (I hope as I can not test it).
After installation, do a
FvwmCommand "Read ConfigFvwmXMMSCtrl"
FvwmCommand "StartXMMSPlayer"
in an a- or xterm
You will not see any windows. To toggle the different xmms-windows you can
do
FvwmCommand "XMMSCommand main 1"
FvwmCommand "XMMSCommand playlist 1"
FvwmCommand "XMMSCommand equalizer 1"
in an a- or xterm. A "0" will hide the windows.
If you feel more comfortable with fvwm's configuration you can add
Read ConfigFvwmXMMCtrl
somewhere in ~/.fvwm/.fvwm2rc
(At the beginning e.g.)
And if you feel even more comfortable

with fvwm you can try do
add the menu called "XMMSMenu" somewhere.
There you can play,stop, start, quit, etc.
To see how it looks you also can do
FvwmCommad "Menu XMMSMenu"
in an a- or xterm.
@zumi
There is at least one drawback, IMHO:
fvwm doesn't know anything about rotation.
If you have a solution...
Christoph