I noticed that there was a bug in Eclipse PDT / ZendStudio PHP Formatter related to the double arrow formatter – it always inserts space before and after the => regardless the configuration you provide. After some hours of debugging (and figuring out how to compile and export Eclipse plugins), I managed to find the reason for the problem and fix it. This article provided some good guidance how to start. I also posted a patch to http://sourceforge.jp/ticket/browse.php?group_id=3881&tid=32198 . It seems that there was a bug that always inserted the space.
However, I didn’t have yet time to figure out how to change the version information, so I have the same file name than the old version, but containing the new patched CodeFormatterOptions. Download the patched version from http://files.phz.fi/pdt_tools.formatter.zip . Install it by unzipping it for example under ZendStudio/plugins/ and then install it to Eclipse/ZendStudio from Help->Install New Software->Add->Local->Browse the directory and the provide some name (PHP Formatter). After this (and restarting) you should be able to find the formatter options from Window->Preferences->PHP->PDT Formatter.