Either I don't understand the question, or you're not understanding the article. The zoom in is automatic.
When the user clicks on an item in the Zoomed Out View, "he will
be taken back to the
zoomed in view, and will be automatically panned/scrolled."
"Consider
for example, the user clicks on “Saab”
in the Zoomed out view. The user will be zoomed in, and will be automatically
panned to
Saab. This automatic panning is handled by the Semantic Zoom control internally and happens when the
user taps or selects an item in the Zoomed out view. This is also referred to
as “Scroll Jump” in MSDN."
Matt Small - Microsoft Escalation Engineer - Forum Moderator
If my reply answers your question, please mark this post as answered.