asterisk users - Aug 2004 - Personal Meetme conferences; is there a better way to do this?

I want to have a "personal meetme conference", so when
on a call I can transfer the other party to my personal conference with
"#7".
(I can then make other calls, and dump them into the conference
using "#7" as well, then join myself by dialing "7").

Using:
  exten => 7,1,MeetMe(${CALLERIDNUM}|Mpd)
this works as long as I originate the call.  However, when I am called
and use "#7", the other party's CALLERIDNUM is used, not mine.

The problem is that I want the "id" of the "transferrer",
and not the
call originator.  I've been able to fix this, but only by modifying
res_parking.c and using a more complicated dial plan. [see below].

It seems like there should be an easier way to do this.  What am I missing?
S

-----------------

Changes to res_parking.c:

  ...
  /* Use the non-macro context to transfer the call */
  if(strlen(transferer->macrocontext))
    transferer_real_context=transferer->macrocontext;
  else
    transferer_real_context=transferer->context;
+
pbx_builtin_setvar_helper(transferee,"TRANSFERER",transferer->name);

"new" dialplan:

exten => 7,1,Wait,1
exten => 7,2,Answer
exten => 7,3,GotoIf($["${TRANSFERER}" = ""]?10)

exten => 7,4,agi(synth|You are being transferred to the other parties
personal conference room)
exten => 7,5,Cut(confname=TRANSFERER,,1)
exten => 7,6,Goto(13)

exten => 7,10,Cut(confname=CHANNEL,,1)
exten => 7,11,MeetMeCount(${confname}|count)
exten => 7,12,agi(synth|Entering your personal conference room with ${count}
other members)

exten => 7,13,MeetMe(${confname}|Mpd)
exten => 7,14,Hangup