I know to access server manager remotely you have to access it via SSL (start the url with https:// instead of http://). As for the other type of access you're talking about you need to have "PC file & print sharing" (the smb service) running. You might also try accessing \yourdomain.com or your i.p: \00.00.00.00 by clicking Start->Run and typing it into that instead of typing it into a browser (especially if you're not using Internet Explorer).
HTH,
Sterling