Programmatically control search providers?

Our program, when installed, asks the user if they want to add our
search provider to MSIE. If the user says yes, we would like to do
the installation without any further questions and without opening up
MSIE, but am I correct in assuming that under MSIE 7 and 8, this is no
longer possible? Even if we sign our installer and ask for
administrator privileges?

And am I also correct in assuming there's no way to programmatically
remove our search provider if the user asks to remove our program?

Thanks,
Chris