You can only negotiate with people that will talk to ya...
That said, If I was Manny, I would try the Shannon Briggs approach lol... just go where Floyd is... bring a camera... have Arum go where Floyd is.. bring a camera.. nobody can say FLoyd didn't have the opportunity to speak to either then.. that's what they should do...
As far as the dead line goes.... meh... it's just an attempt to get Mayweather to the table.. I wouldnt read too much into it guys.. Mayweather has shown before that he will sit for long periods of time... negotiating with him leaves you with a choice.. sit with him.. and waste the golden days of your career... or try to get him to the table before we have a "GRUDGE MATCH" situation