Editing a file path in an XML File

So I am trying to change a path to INSTALLDIR but with double slashes.

I am using the XML file section.

In the attached screen shot, you can see the file path outlined in read.

If I just put [INSTALLDIR] there, then when I run the installer, it puts the install dir with single slashes instead of double.

Does anyone know a way around this to get the double slashes?

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