How to Invoke a SharePoint 2010 Alert using Web Service Call

Question

Is there a way to invoke (call) an existing immediate alert subscription using a web service call?

I have a requirement from a user who would like to receive a formatted Alert email whenever certain properties change on a list item.

This is a conditional type of alert, which I can do from a SharePoint workflow.

However, I need to be able to invoke/call a specific Alert from the workflow, presumably using web service calls. 

I can see there are 2 methods in Alerts.asmx (GetAlerts and DeleteAlerts) but I don't see a way to invoke one that's out there.

 

Any ideas would be appreciated.