Patching FreePBX asterisk

Hi folk, I am pretty new on asterisk world so maybe this question could seams really easy for someone. I have istalled a FreePBX asterisk box ( using ISO image ). I upgraded FreePBX and Asterisk as well by using Admin module tool. I have integrated asterisk with Exchange UM 2010. Everything works fine except fro MWI. I read that this patch " https://issues.asterisk.org/view.php?id=18762" solves the issue. My problem is that I don’t really know how to apply this patch. I read that I have to have asterisk sources on /usr/src. Following what I did:
1- downloaded asterisk-1.8.4.3.tar.gz
2- unpacked on /usr/src/asterisk/asterisk-1.8.4.3
3- applied wget ‘https://issues.asterisk.org/file_download.php?file_id=28523&type=bug’ -O - | patch -p0
4- ./configure
5- make
6- make install
7 ( everything without errors!!! )
8- rebooted entire system but I get same issue of preview state.

What’s wrong? How can I be sure that patch is applied?
Thnaks in advance.
2 days ago

No Idea???

Assuming the patch successfully applied your Exchange trunk in FreePBX needs [email protected] added. Once added mark a voicemail unread / read. This will cause Exchange to send the MWI event. Then on the Asterisk console execute “event dump cache MWI”. You should see the mailbox in the exchvm context with the correct new and old messages. After you have verified it is working each FreePBX device the mailbox setting needs to be configured to [email protected]