There was a conversation thread about this that was started via the features e-mail address also. It looks like we're dealing with the shotgun approach here - which usually doesn't work as well as you want since you get different replies and it just leads to lots of extra work.
When your custom app is in the foreground, you've got control of the keys, and pressing the hardkeys or DTMF keys doesn't push those events down into the phone application. With what we have, making that kind of a change isn't a simple-to-do.
You do have access to the onkey (
http://phones.digium.com/content/onkeykey) handler, that'll let you grab a key and then perform other things, e.g.
http://phones.digium.com/methods/digiumphonesenddtmf or the other methods at
http://phones.digium.com/phone-api/refe ... igiumphoneThe best advice currently is to just grab a softkey that backgrounds your app into an idle screen app, with your important information, then the user can interact however they want with a call, and you can use a BLF key to bring that app back into the foreground.
Cheers