Well I have two that are home all day for a long period of time since both hubby and I work. Best advice is to not make a big deal out of leaving. I've watched several of Victoria Stillwell's training on Animal Planet and you put the dog in their x-pen and leave without saying a word and same when you come home. Don't make a big fuss over it..it should be like any other time you come and go.
Also I leave busy toys for both..like puzzle toys you put treats in. So when I leave they both go into their separate pens, I leave them their busy toys and walk out the door. It works trust me.
Also since Cosmo is still a puppy and in puppy potty training I have to keep him in his x-pen more often especially when I'm getting ready for work (husband is already gone by the time I even get up). So when I go upstairs to get ready Cosmo goes into the x-pen and in the beginning he used to bark and cry his head off. I stood my ground and ignored him.
Victoria Stillwell says ignore that way they stop. If you do anything while they are barking, whining and you talk to them or give them something they think to themselves..wow..I barked/whinned and I got attention frrom Mom and Dad. Bingo I'll keep doing it.
Hope this helps a little.
Oh it took about a week then it started to get better but don't cave in to their cuteness..hehehe