I am looking for a python SOAP 1.2 client but it seems that it does not exist . All of the existing clients are either not maintainted or only compatible with SOAP 1.1:
I have had the very similar problem some years ago and I have solved it by using Jython.
If there is no existed implementation of SOAP 1.2 for Python, you may be interested in Jython, which seamlessly integrates you with the Java platform. It means, you can use any of the existed SOAP 1.2 Java classes and just import it into your Jython program. Your Jython program is just your Python program, but you can import Java classes.
Jython itself includes almost all of the modules in the standard Python programming language distribution, but be sure that your program does not use any special non-standard Python library.
Example: say, you have Jython installed (it is free and Open Source) and your Python program is called myprog.py and you want use Java class CLASSNAME:
1) import required Java class inserting import CLASSNAME
into your myprog.py
2) run jython myprog.py