Django User authentication when password is stored on different system

I am making an web application that have to be integrated with other system using SOAP for communication between them. The problem is that I need to have users and store application specific information for them, but store the password on other开发者_JS百科 system. So when the user enter his password username/password I have to make check on the other system and if this user exists and this is his password to log him in on my application.

So my question is how can this be done.

You have to write your own authentication backend!