[Freeswitch-users] question about the conference module: DTMF collection via XMPP?

I am actually not yet a user of FreeSWITCH, but I have been reading the online documentation to determine whether or not I could use it as part of a project I am currently working on that requires conferencing. I see that there are caller controls that can be used to play audio files to specific participants in the conference, using XMPP. I need to play an audio file and then be notified if/when the participant acknowledges the prompt in the audio file by pressing a DTMF key. I do not see a way to do this according to the documentation, but maybe there is something I am missing (or something not documented). Do any of you out there know of a way to collect DTMF over XMPP? Thanks, Brian