asterisk users - May 2012 - Sound file format and Asterisk 1.8.11-cert1

Hi All;

I installed Asterisk 1.8.11-cert1, and it look like the default is ulaw for the
sound files. How I can fix this?

Athough file beep.gsm is existed under path (/var/lib/asterisk/sounds/en), but
when I used the Record function, it gave me the following (so I am sure there is
something that can let asterisk accept beep.gsm), what could be?

[May  5 00:44:16] WARNING[2262]: file.c:663 ast_openstream_full: File beep does
not exist in any format
[May  5 00:44:16] WARNING[2262]: file.c:958 ast_streamfile: Unable to open beep
(format 0x4 (ulaw)): No such file or directory
[May  5 00:44:16] WARNING[2262]: app_record.c:285 record_exec: ast_streamfile
failed on DAHDI/1-1

Regards
Bilal