case-sensitive configparser without magical interpolation?

[georgeryoung at gmail.com]

[python 2.7]
I need to use a configparser that is case-sensitive for option names, but does not do magical interpolation of percent sign.  
I.e.:

[Mapping0]
backupHost = eng%26
dbNode = v_br_node0001

should be read (and later written) as is, including capitalization and the percent sign.  

I find that RawConfigParser keeps the %, but downcases the option name.
And SafeConfigParser can be hacked with optionxform to be case-sensitive, but does interpolation.
How can I get case-sensitive but no interpolation?

-- George