Actually, the examples directory in the distro for the development release has a nice program to create an element and print it to stdout called SimpleTestBool.hs:

module Main where

import List (isPrefixOf)
import Text.XML.HaXml.XmlContent
import Text.XML.HaXml.Types
import Text.PrettyPrint.HughesPJ (render)
import Text.XML.HaXml.Pretty (document)

-- Test stuff
--value1 :: ([(Bool,Int)],(String,Maybe Char))
value1 = True

--main = do (putStrLn . render . document . toXml) value2

main = fWriteXml "/dev/tty" value1