xmimd will help here, at least while waiting for a more properly integrated solution.

Since you are not using a chroot or Xephyr, this usecase is much easier. Just do:

1. Install the xmimd package
2. Open a terminal window and run "xmimd -v". Leave it open.
3. On a second, newly opened terminal window, run
   
   Code:

   export GTK_IM_MODULE=xim
   export XMODIFIERS="@im=xmim"

4. On the second terminal window, run "pidgin".

The Gtk+ window will not be resized, making it hard to see what you've written, but at least you won't need the bt keyboard...