The method for adding an article shouldn't really depend on how you
initialized it. Issuing a call to sp_addarticle will suffice. One
thing I've run across though is that the sync_method, immediate_sync,
and allow_annonymous_subscribers properties defined on the publication
affect what will happen when you generate the snapshot for the new
article. If sync_method is "snapshot", immediate_sync is false, and
allow_anonymous_subscribers is false, then the snapshot will be
generated only for your new article. If they're anything else, a
snapshot will be generated for all articles in the publication. And
that can be a real pain. Hope this helps!
--
Ben