yes this is possible with asterisk box
for that voicemail config sud be properly config with this parameters
serveremail = email@example.com
sendvoicemail = yes
mailcmd=/usr/sbin/sendmail -v -t -f firstname.lastname@example.org
7788 => 11,john,email@example.com or ur gmail id
above is ur extension 7788 voicemail settings
also in sip .conf u have to set mailbox=7788 for that use config.
above is important settings to work voicemail to email notification other things in voicemail,sip,extenson.conf are same as u config.
one more thing plz check at ur server sendmail application is ON. which is in int.d file check that also.