Custom Installs and Vista

I have a question about customizing Windows application installs than
installing them on Windows Vista. For example I customize the install
for Thunderbird to have all the default values set so when we setup a
mail account we do not need to change any options. Now the problem
that I am having is after I install Thunderbird on a vista computer
each time they run Thunderbird it prompts a security certification
issue. Now there is an option to remember this setting but even
though I put the check box in that each time I run Thunderbird it
still prompts asking if they want to run it. Is there anyway that I
can add this program to a list somewhere so it won't ask them if they
want to run it or is there something that I can do to the install so
this doesn't happen?