Mmmm.. thus far, none of the server software I've tried/hacked has provided FF/REW.
But now I've stumbled across a strong recommendation for
Serviio.
No joy there, either. Thus far, nothing has done it any better than MythTV's built-in server, so I'm sticking with that.
I haven't actually see anyone post that FF/REW works for them on a "C" series ("C" == 2010) Samsung TV, with _any_ server. So perhaps Samsung have simply not enabled FF/REW for DLNA access.
Weird though, because the uPNP browsers I've tried out show that the TV does report some kind of FF/REW support.
Cheers