Issue with dialog open function

I'm testing out the new 1.6rc4 release along with jQuery 1.3b2, and
I've found what looks to be a regression with the new jQuery version.
I'm creating a dialog with an open function declared: $
("#dialog").dialog( { open: function() { doStuff(); } }).dialog
("open"), and my custom open function isn't being called. If I used
1.6rc4 with jQuery 1.2.6 it's working just fine.
Thanks,
Jason