Error trying to use php 5.6 Calendar extensions (calendar.so)

Hi,
I’m trying to use the cal_days_in_month function enabled by the php calendar extensions

I’m getting the following error when trying to run the code in my scriptcase development environment :
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Fatal error: Call to undefined function cal_days_in_month() in/opt/NetMake/v81/wwwroot/scriptcase/app/app.php[/TD]
[/TR]
[/TABLE]

I have tried adding the following line in the /opt/NetMake/v81/components/apache/conf/php.ini file :
extension=/usr/lib/php/20131226/calendar.so

I restarted scriptcase , but I still get the same error, I do not have the problem when I deploy the app to test.