Unfortunately Eclipse has its own mechanism for keyboard settings, so that the global changes in Mac OS are ignored.
Reconfigure the keys as described below:
|Select Line Start||<key>S-Home</key>|
|Select Line End||<key>S-End</key>|
|Select Text Start||unset|
|Select Text End||unset|
The screenshot below helps you finding the settings:
Firefox does not regard changes in keybindings. Use the Keyfixer add-on to get PC-like behaviour.