Doxie's as a breed are known as being excellent watchdogs/doorbells. So, some of what you are experiencing is a part of the breed.
I prefer the 'caught accidentally doing good' technique for training. In this situation, this means applying the stimulus, a boisterous entry, over and over again. When she happens to do anything but bark (like lick her paws), reward her. This could be with a food treat, but be careful as doxies tend to pack on the pounds! For my doxie, Peanut, the desired behavior is rewarded by my singing her a song I made up about her.
This will require buckets of patience on your part. I have successfully used this technique for housebreaking, walking on a leash, barking, and not licking my mouth. (She is allowed to lick my arms and neck!) Mind you, I have lots of time on my hands!
I have some follow up questions, which may generate more tips:
You mentioned that you tried training. What did that entail? How long did you persist?
How old is your doxie? Did she come from a loud environment?
Is there fear and/or aggression directed at the one being barked at? Or, does she seem to want to play? Is she 'guarding' you when she barks? (They tend to be possessive of their family).
What seems to be the purpose of her barking?
Finally, remember that Dachshunds tend to be dominate. While you may plan on training them, they actually will be training YOU! They key is to be more stubborn than she is!
Let us know how it goes,
Guy