introducing an unsocialized dog

Question
I have two well socialized dogs.  One is a nine year old pitt bull mix and one is a 9 mos old border collie.  I rescued both my dogs and since I will likely rescue other dogs to foster, I make sure I socialize my dogs continually.  I have recently taken on a foster miniature dachshund.  She is about a year old and totally unsocialized.  She is aggressive to my dogs.  I have been trying to introduce her in brief sessions and putting her in her kennel when she gets snarly.  I walk her with my older dog.  I keep her kennel in a room where she can see and smell my dogs.  She eats with them with no problem.  She just gets scared if they pay her any attention and then she goes off like a rocket.  My dogs are both well balanced and just ignore her for the most part.  However, I feel like I am losing ground and thus patience with this dachshund.  

Unfortunately, she will be with me for a next few mos. and there is no where else she can go.  She will be placed in a permanent home with no other dogs, so it won't continue to be a problem after her permanent placement.  I just hate thinking that I can't train her to be less fearful of other dogs.  Any suggestions?

Answer
Just remember, when it comes to training, slow is fast.  Start with the doxie at a distance where she is comfortable and not reacting to the to the other dogs.  Reward her for being calm and not reacting.  Move in a foot and repeat.  Keep moving in until she reacts.  Don't reward and back off.  Move back to where she was last comfortable, reward and quit the session.  You should be able to slowly move closer and closer without her reacting.  It is, however, a slow process.  You might just be getting her used to your dogs by the time she's ready to leave.

Good luck.