I just bought Sony's dual-layer burner and now I'm trying to burn a 4 hour video onto a DVD+R DL disc. Sony Architect doesn't seem to want to recognize it.
You can't get there from here. DVDA does not suppot DL buring, nor does it support DL projects in general (though it does let you produce such projects).
surf over to www.vso-software.com and get a copy of CopyToDVD which does support DL burning. I've burnt a DL project from DVDA using this software and it does work.