How to Add Microsoft.EnterPriseCloud.Monitoring.MicrosoftMonitoringAgent Extension in Azure VMs.

I want to add Microsoft.EnterPriseCloud.Monitoring.MicrosoftMonitoringAgent Extension in VMs in Windows Azure. How Can I Add this Extension. I was went in Extension section of VMs in portal.azure.com and try to add this extension using add button but I can not find this extension here and Please help me.

Thanks

Shahzad