there are several easy ways to make an adaptor for this.
if you have a F-xlr to M-trs, you can modify it inside either connector to accomplish your goal.
in the xlr connector, move pin 3 wire to combine with wire on pin 2 [technically you should then jump pin 3 to pin 1, but it'll probably work fine if you don't].
or
in the trs, disconnect ring and jump ring to tip.
you could also open the box and accomplish the same thing by moving the wire from the 'ring' connection to the 'tip' connection.
all of these make your connection unbalanced, but that is probably not a big deal for your purposes...
if you've got access to a 'electrical engineer' drummer, these mods should be a piece of cake. 10 minutes and a soldering iron.
and yeah, it should have a mono switch...
brian maddox
'cheap gear personalizer'
brianm@fcfchurch.com