Thanks for helping - what we eventually did that day a couple of days ago was going to another machine that was not mission-critical so we could cycle SQL services and implement the new LUN and our recovery issue through it. This worked fine and our issue is no longer an item.
Bottom line - we never found a means of attaching a LUN to the SQL Server without turning off services and adding dependencies. Otherwise, even though Windows Explorer could "see" the added LUN, SQL could not - plain and simple. No way to force it, that I could find, on-the-fly...