It sounds like your doing it right.
Some pups protestant more than others. I try to find their favorite treat, and they only get it in the crate. With her, it might be she only gets it if your leaving.
Also try playing crate games with her.
Do you know if she's crying the whole time your gone? Some settle, but start back up when they hear you.
Try also playing the radio when home, and its time for her to relax. I use classical music. Hopefully she will then start keying on it meaning time to settle, and not you leaving.
My adult dogs, don't like to have a door shut between us. Well they don't mind it, if they are napping on my bed. But its because they have chosen to rest there.
Not all those who wander are lost.
Life is just a leap of faith.
Spread your arms and hold your breath and always trust your cape.
Two things define you. Your patience when you have nothing, and your attitude when you have everything.