How to let my boyfriend know that I want him to say hi first?

So, on facebook chat, or msn convo's I always seem to say hi first nowadays... And it's really fustrating me. When I do say hi, we end up having a good convo. BUT I want him to say hi first now! How do I let him know? In a discrete kind of way? Pleaseee... NEED HELP. Thaaanks :)