wix - Editing file with msi-installer -

i need update software without replacing software's config-file. config-file must upgraded (add lines). possible edit config-file msi (created wix) without replacing it?

<component id="com6e3e974d3fe541ed8554485c716e6f40" guid="{841fb431-8a04-4ee8-a53f-80a5af8f3aa3}">       <removefile id="a21" name="n4gwsrv.exe.config" on="install" />        <file id="fil20a15c96a7db4fa7924651e80c05764e" name="n4gwsrv.exe.config" keypath="yes" diskid="1" source="c:\atm\n4gwsrv\n4gwsrv.exe.config" /> </component> 

thanks adrian faciu link how modify .net config files during installation?

also helped http://blogs.technet.com/b/alexshev/archive/2009/05/27/from-msi-to-wix-part-25-installable-items-updating-xml-files-using-xmlfile.aspx