Never mind, after a little further testing I found the answer.
For anyone interested in this, I placed the link code in the 'XHTML' section of IndexPage. Within there, I created a new routine, selected After <head> as the location, and then just put the following code:
<link rel="apple-touch-icon" href="/Images/ourapplicationicon.png"/>
(where ourapplicationicon.png is our PNG icon in a 57x57 pixel resolution - at least for the iPhone and should work for android as well. For ipad, use 72x27 pixel resolution).
The icon file itself is placed in the Images subfolder of the Web folder.
Works like a charm.
Bob