Everything and the Mobile Software Universe…

Interesting read :
Agile Chronicles: Can Gantt Charts be Agile?

We try to put in place Agile methods here, but even if as software developpers we strongly believe in the iteration process and so one : we have traditional clients that need to know Date/Schedule/What is in a release/Is the project going late? by how?. And for me, and for now, even if Task/user story are “agile” in our process, I need a Gantt Chart to give DATES/DEADLINES/SCHEDULE to my hierarchy, taking into account my team holidays, the impact of bug fixes vs features coming from different clients.
I’m incomfortable in respect to Agile methods because of this deadline thing:

• Either client/management has to adapt and forget the deadline stuff, accepting many incremental changes and releases….hum forget the incremental release stuff in the embedded space, with those awfull build systems.
• Agile has to be adapted to present a Schedule and Deadline frontend … because it is what PEOPLE understand, forget team velocity, % completion, etc, the only things clients/hierarchy want to know is by how much days you will be late

What do you think? what solutions did you put in place to make Agile compatible with businesscases?