Let meetme choose ulaw

how to let meetme choose ulaw?
now iaxclient have surpport two kinds of codecs. one is ilbc the other is ulaw. then in iax.conf i set allow as followings
allow=ulaw
allow=ilbc

when user call normal phones i expect iaxclient use ilbc ,when call conference i expect ulaw . but it seems that the server always use the same codec. if i put the “allow =ulaw” ahead the actual codec will be ulaw .if i put “allow=ilbc” ahead the actual codec will be ilbc.
how to solve such a problem?
is there any way?
thanks very much!

I meet the same problem

There is currently no way to define a codec used by a VOIP client based upon the application being used in Asterisk(Dial, Meetme, VoiceMail, etc…).

That is a user using G729 will not use meetme function,is that so?