Vista - Vista and HTAs

I have a series of HTAs I use to do initial system configuration under the
local administrator's ID. They work well on XP, but they fail on Vista
(5308). They're not throwing any error messages, but I'm seeing failure at
a couple points. First, an initial HTA launches when you log on as the
built-in administrator to get the tech's credentials and connect to a
network share to launch another HTA that actually does the work. The first
script (local) does run and does call the second script (from the server),
but the second does not appear. NET USE shows that the share is mounted and
Task Mgr shows that mshta is running, but the GUI is not visible. The
second failure point occurs if I actually launch the server-based HTA.
There's logic in it to unload and reload the HTA with different data if
requested by mouse click. Initially the HTA runs, accepts input, and it
appears that the unload and reload happens, but again the GUI is not
visible. In this case too Task Mgr shows that mshta is running.

Obviously Vista is handling these HTAs differently than XP. And I'm seeing
more security warning messages ("are you sure you want to run this" type
messages) when I launch the HTA in the first place. These are annoying, but
less of a concern because you can actually navigate through them to allow
the script to run.

Can anyone point me to some documentation that explains how Vista handles
HTAs (and VBS scripts) differently from XP? Or even explain it to me
directly?

Thanks,

Tom