Don't know about 'accepted' but one detail I've used is to make the beam pocket larger than the beam by about 1" side to side and 1/2" taller. Line the inside of the beam pocket with ice and water shield, insert beam, shim it tight so it has torsional stability, and that's that. Beam is bearing at the appropriate level, there's a barrier to prevent moisture from coming at the beam directly, and ventilation at the beam end so the wood can dry.
You can also paint it with an asphalt based paint (like the stuff they make for direct embed fence posts), and I've spec'd that, too, but I've always been concerned about sealing the ends of the beam. Most moisture transfer happens along the length of the beam, and it's easier for the wood to dry from the ends.
