[P-did]

Some techiques I've been using with our pup to make her like her pen:

1) When I'm watching her and she's allowed to roam, I hide tiny bits of chicken all around her pen. After doing this for a day, she regularly spends time in her pen when the door is open.

2) When she is quietly in her pen for a given amount of time (build it up slowly), she gets a click and a treat.

3) When I'm getting ready to leave or to go to bed, if she stays on her bed and calm, she gets a click and a treat.

In other words, the pen needs to be thought as a fun place.

And of course, like you said, ignore the barking.

I believe in the positive training school of thought, in which you ignore the bad behavior and reward the good. Negative feedback should be given to the dog verbally, not physically.