replacing sections in XML

[VBuild_Rookie]

I want to be able to replace sections of the XML file using visual build. Is this possible I have no clue on how to do this but I just need to change sections of config files (.NET) for diff enviroments

<appSettings>
<add key="DatasourceConnection" value="blah lah" />
<add key="ServerlessLDAPBinding" value="blah" />
<add key="ActiveDirectoryServer" alue="blah"/>
<add key="NewtonUsersOU" value="blah"/>
<add key="NewtonUsersOUContainer" value="blah"/>
</appSettings>

WITH
<appSettings>
<add key="DatasourceConnection" value="NEW blah lah" />
<add key="ServerlessLDAPBinding" value="NEW blah" />
<add key="ActiveDirectoryServer" alue="NEW blah"/>
<add key="NewtonUsersOU" value="NEW blah"/>
<add key="NewtonUsersOUContainer" value="NEW blah"/>
</appSettings>