Newbie question: initial value with external itemset?

Hi all,

 

I'm studying XForms and have hit a wall trying to reconcile this nifty
wikibook-documented "best practice" for using an external itemset for a
select1 element:

 

http://en.wikibooks.org/wiki/XForms/Selecting_from_File

 

.. with this w3.org-described method for providing an initial value:

 

http://www.w3.org/MarkUp/Forms/2003/xforms-for-html-authors.html#InitialValu
es

 

No doubt I'm overlooking something obvious.

 

Thanks for your patience with this newbie.

 

Jeff

Toronto