GSM codec in Minisip

[jers at inwind.it]

Hi all,

I wish to use GSM codecs in minisip r2659 on Debian, but setting the codec tag "GSM" in the profile configuration file, I obtain the message "AudioCodec not found name: GSM". I looked in the Codec.cxx of libminisip and I noticed that it includes only the G711CODEC header file. The GsmCodec.h, instead, seems to be left out. 

In a previous message it is suggested to use GSM codecs plugins. No minisip-plugins package is in r2659. In the last trunk (r2698) there is a file minisip-plugins.install listing some libraries. 

In the following my doubts:
1. Is GSM codec usable in minisip? 
2. If so, how can I do that?
3. If I must use plugins, how can I find  and install them?

Thank in advance.
Regards

Jers