OK, finally got it working. Great fun! This is going to be a good substitute for sunspots.
There are a couple of gotchas that I ran into. Watch out that CSS really takes control of your keyer via F keys. I had a couple of false starts where I was transmitting on the air before realizing that CSS wasn't in control. Put your K3 in TEST mode just to be safe.
Also, make sure your "call" F key has the same call as in the Setup otherwise the CQing stations won't answer you.
If you don't get a call, put a question mark as one of your F keys. That seems to be the same as calling CQ. Going back to a partial call doesn't really work as in real life where maybe half the pileup stays quiet and the guy you want is easier to copy.
Running a pileup is quite realistic although it could be better, and at the rate Wayne is moving this may catch up sooner or later. One thing that I'd like some QRN just to make the realism better.
Another problem is that stations give their call once and then stop. That's not at all realistic. EU stations should keep calling even if you call someone else.
Also you can't do a directed call such as CQ NA. The EU stations still call. OK, I guess that is realistic. :-)
The faster you work down a pileup the fewer stations remain in the pile. Now that's a realistic situation I've never seen in a simulator before. Also fun .. in a masochistic way .. to have a station start CQing right on top of your run. Now that's realism! You can't win a frequency fight with a robot so don't try.
73, Alan AD6E