You could reassign the keyboard shortcut for Go to Start Page in System Preferences>Keyboard & Mouse>Keyboard shortcuts.
To do so, click the + button in the preferences window (bottom left), select OmniWeb from the Application: menu, type in the option for which you want to change the shortcut (
Go to Start Page which is in the History menu of OmniWeb), click the input box for the shortcut and then press the keys that you want to use as your new shortcut (e.g. add option to the current default) and it should show up in the entry box. Click Add. If OmniWeb was open at the time, you will need to quit and re-launch it for the change to take:
