I want to activate Site mail boxes(CollaborationMailboxFarm) Farm level feature in central admin programmatically.

I want to programmatically activate Site mail boxes(CollaborationMailboxFarm) Farm level feature which is having "3a11d8ef-641e-4c79-b4d9-be3b17f9607c" ID.

for this i created a feature and i am writing code in FeatureActivated event.

Can any body help me on this. 

public override void FeatureActivated(SPFeatureReceiverProperties properties)
        {            
            foreach (SPFeatureDefinition feature in SPFarm.Local.FeatureDefinitions)
            {
                if (feature.Scope == SPFeatureScope.Farm)
                {
                    if (feature.Id.ToString()=="3a11d8ef-641e-4c79-b4d9-be3b17f9607c")
                    {
                       // Code for activating the Site mail boxes(CollaborationMailboxFarm) Farm level feature.
                    }
                }
            }

        }