Most of the time you need not manipulate the application by automating mouse clicks. Script the usage of keyboard shortcuts for any functionality you like, use TAB to navigate to buttons, and ENTER respectivelly to activate them. This can be done by exploiting the Windows Scripting Host.
in reply to perl library for controlling Windows GUI (like AutoIt)
You can read more about sendkeys'() peculiarities here: Microsoft link. Of course, you should check if the relevent applicantion exposes some functionality via an OLE server. In that is the case, see if you can get hold of its "Scripting Guide".
my $wsh = new Win32::OLE 'WScript.Shell';
my $targetExactWindowName = "The exact window title of your applicatio
# This brings it to the foreground
$wsh->AppActivate( $target );
# Type some keys in the Window, here Ctr+P followed by Enter