In case you hadn't worked it out...
take your total number of posts, subtract 1
then in the url it takes you to on the search, change the startfrom number to that..

So for you it should be www.b3ta.com/users/searchposts.php?id=21744&board=talk&start=15301

although that doesn't seem to work for me...
( The Teviot Moose major 5th., Wed 14 Dec 2005, 17:11, archived)

yeah, seems you can't look at other's posts past a week

( Boondocks, YEAH! has a massive penis. Everyone is scared., Wed 14 Dec 2005, 17:17, archived)

Damn, there goes that idea for blackmail...

( The Teviot Moose major 5th., Wed 14 Dec 2005, 17:19, archived)