The ugly cmd box that appears when using portable.bat has now gone thanks to Faih Kodak and Bat To Exe Converter
(Bat To Exe-Converter converts batch-script files to exe files.). The batch is now an exe and runs invisible now and comes with a snazzy icon - download mine if you dont want to make your own here: http://www.d-sine.com/download.php?f=portable.zip
and just replace your portable.bat with this.
Should work with all versions. enjoy