You can try by using vmware_guest_sendkey module to send keyboard input to boot loader menu, edit boot menu entry to add path to preseed.cfg (served on some HTTP/FTP server) and then boot the machine. I have personally not tested this but it should be achievable. There is a catch though, you cannot send an arbitrary combination of special keys and characters. You have to call the module multiple times, first by sending some special keys, then some characters, then some special keys and so on. Please consult the documentation for details: