[Help] Man. API: User hangup in conference => conf. ends

I have an application using the Manager API and the Asterisk-Java framework.
When I start two outgoing calls (by using the OriginateAction) and start a meetme conference (by using the context ‘meetme1’, see below), this conference works correctly. But when one of the participants hangs up, the other one is hung up too (and further extensions in the dialplan are not triggered). This is not what I want, I want the other one to stay in the conference room.

This problem does not occur, when I don’t use the manager API but simply connect two incoming calls in a conference (see default ‘context’ below).

Asterisk version is 1.2.1.

The simplified extensions.conf:

exten => s,1,Goto(meetme1,s,1)

exten => s,1,meetme(1)

I haven’t found anything on this issue, any help is appreciated.

I have examined the case a little further:

I initiate a conference with person A and person B.
A intitiated the call himself and was directed by the dialplan whereas
B was called and directed by the Manager API.
When A hangs up, B stays in the conference. When B hangs up, A is hung up too.
=> It looks like when someone, who was directed by the Manager API, hangs up while being in a conference room, that conference is closed.