How to write kickstart file containing non-common characters like # or \

Issue

Kickstart file is a URL specified as following:

url --url ftp://domain\\username:password#@hostname:/rhel61-x64

The password contains a #.

Now when we start the system we get the error:

But then we get the python error:

File "/usr/lib64/python2.6/shlex.py", line 191, in read_token raise ValueError, "No escaped character"
ValueError: No escaped character
install exited abnormally [1/1]

And last thing we tried is to put within quotes:
url --url 'ftp://domain\username:password#@hostname/rhel61-x64'

And then we get the python error:
File "/usr/lib64/python2.6/shlex.py", line 172, in read_token raise ValueError, "No closing quotation"
ValueError: No closing quotation
install exited abnormally [1/1]