Slipstream with an interview xml script

I want to create a sort of unattended script. That is where a lot of
things (key, etc) are already entered in, but a unique script is
kicked off that will interview the installer as to a few questions. I
have the script provided to me by the client, I just don't know how to
integrate it into the unattended.xml file so that it kicks off.

Can anyone point me the write way?

Thank you,
Jim