Create Custom Requirement based on a Service that is running

Hi all,

SCCM 2012

I need to deploy an application only to Windows 7 devices that have the service 'wlansvc'running.

When creating a Custom Requirement I have to create a new Global Condition (which can be a setting type or an expression type).

How do I create a Global Condition that verifies that the 'wlansvc' service is running.

Any help appreciated.

Thanks