asterisk users - Jun 2010 - Announcement before absolute timeout / how to terminate a meetme conf?

Hi,

I'm new to asterisk and have a little trouble in developing my first more
complex dialplan. The basic task is a click to call solution:

- call one number via sip, play some announcements, do cdr etc. and put
the callee into an conference room with music on hold
- call a second number via sip, play some announcements, do cdr etc. put
the callee into the same conference 
- have a nice chat
- play an announcement and kill the conference after a max time value

so far so good. I developed the following Dialplan to fulfill the task
(simplified, hopefully right - deleted all announcements, cdr, etc. :)):

[macro-c2cmacro-p1]

exten =>
s,n,Dial(SIP/sipconnect/${to1},120,M(c2cmacro-connect^${ARG1}^to1))
exten => s,n(lbl_macro-c2cmacro-p1_1),MacroExit()
exten => s,n(lbl_macro-c2cmacro-p1_2),Hangup()
exten => h,1,MeetMeAdmin(8000,K)
exten => h,n,Goto(s,lbl_macro-c2cmacro-p1_1)

[macro-c2cmacro-p2]

exten =>
s,n,Dial(SIP/sipconnect/${to2},120,M(c2cmacro-connect^${ARG1}^to2))
exten => s,n(lbl_macro-c2cmacro-p2_1),MacroExit()
exten => s,n(lbl_macro-c2cmacro-p2_2),Hangup()
exten => h,1,MeetMeAdmin(8000,K)
exten => h,n,Goto(s,lbl_macro-c2cmacro-p2_1)

[macro-c2cmacro-connect]

exten => s,n,Set(TIMEOUT(absolute)=120)
exten => s,n(lbl_macro-c2cmacro-connect_2),MeetMe(8000,Mqo,1238000)
exten => s,n,MacroExit()

The dialplan does the job quiet well, but one small problem remains and is
driving me nuts: As you can see there is an absolute timeout defined. 60
second before the timeout is reached an announcement should be played into
to conference. I tried google and found out that a zaptel device is needed
to use e.g. an AGI script within the meetme conf (which I can't because
then music on hold is gone?!). I only have sip and ztdummy available on the
server ;( 

I also tried timeouts with announcements within the dial commands, but the
timeouts didn't have any effects for the callees or the conference.

The most promising link I found was:

http://www.mail-archive.com/asterisk-users at lists.digium.com/msg22182.html

but this stuff is very old.....

Do you have any suggestion what I can do to work this out?

Kind regards

Markus