I am testing GMiner 1.52 against a test pool that passes a block height of 321321 back to the miner so I can see what settings might be best for my GPUs after the hard fork.  We have noticed that it will only successfully mine if we use algo=BeamHashII, forcing the new algo.  If we use algo=BeamHash, which should auto-switch at block 321321, it does not work.  What is the technical mechanism Gminer will use to auto-switch the algo at the fork height?

Thanks