My setup for 'KeyRemap4MacBook' to get some German Keyboard habits to US-Layout to usel: 'Open KeyRemap4MacBook Preferences...' > Go to 'Misc & Uninstall' > Click 'Open private.xml' > add all Files

private.xml

<?xml version="1.0"?>
<root>
    <include path="set_option_l_to_at.xml" />
    <include path="set_option_e_to_euro.xml" />
    <include path="umlaut_access.xml" />
</root>

set_option_e_to_euro.xml

<?xml version="1.0"?>
<root>
    <item>
        <name>Set 'option + E' to €</name>
        <identifier>private.set_option_e_to_euro</identifier>
        <autogen>
            __KeyToKey__
            KeyCode::E, ModifierFlag::OPTION_L,
            KeyCode::KEY_2,   ModifierFlag::SHIFT_L | ModifierFlag::OPTION_L
        </autogen>
        <autogen>
            __KeyToKey__
            KeyCode::E, ModifierFlag::OPTION_R,
            KeyCode::KEY_2,   ModifierFlag::SHIFT_L | ModifierFlag::OPTION_L
        </autogen>
        <autogen>
            __KeyToKey__
            KeyCode::KEY_2,   ModifierFlag::SHIFT_L | ModifierFlag::OPTION_L,
            KeyCode::E, ModifierFlag::OPTION_L
        </autogen>
    </item>
</root>

set_option_l_to_at.xml

<?xml version="1.0"?>
<root>
    <item>
        <name>Set 'Option + L' to @</name>
        <identifier>private.set_option_l_to_at</identifier>
        <autogen>
            __KeyToKey__
            KeyCode::L, ModifierFlag::OPTION_L,
            KeyCode::KEY_2,   ModifierFlag::SHIFT_L
        </autogen>
        <autogen>
            __KeyToKey__
            KeyCode::L, ModifierFlag::OPTION_R,
            KeyCode::KEY_2,   ModifierFlag::SHIFT_L
        </autogen>
    </item>
</root>

umlaut_access.xml

<?xml version="1.0"?>
<root>
    <item>
        <name>Easy access for Umlauts</name>
        <identifier>private.easy_umlaut_access</identifier>
        <!-- Capital with OPTION_R and SHIFT -->
        <autogen>
            __KeyToKey__
            KeyCode::A, ModifierFlag::OPTION_R | VK_SHIFT | ModifierFlag::NONE,
            KeyCode::U, ModifierFlag::OPTION_R, KeyCode::A, VK_SHIFT
        </autogen>
        <autogen>
            __KeyToKey__
            KeyCode::U, ModifierFlag::OPTION_R | VK_SHIFT | ModifierFlag::NONE,
            KeyCode::U, ModifierFlag::OPTION_R, KeyCode::U, VK_SHIFT
        </autogen>
        <autogen>
            __KeyToKey__
            KeyCode::O, ModifierFlag::OPTION_R | VK_SHIFT | ModifierFlag::NONE,
            KeyCode::U, ModifierFlag::OPTION_R, KeyCode::O, VK_SHIFT
        </autogen>
        <!-- Capital with OPTION_L and SHIFT -->
        <autogen>
            __KeyToKey__
            KeyCode::A, ModifierFlag::OPTION_L | VK_SHIFT | ModifierFlag::NONE,
            KeyCode::U, ModifierFlag::OPTION_R, KeyCode::A, VK_SHIFT
        </autogen>
        <autogen>
            __KeyToKey__
            KeyCode::U, ModifierFlag::OPTION_L | VK_SHIFT | ModifierFlag::NONE,
            KeyCode::U, ModifierFlag::OPTION_R, KeyCode::U, VK_SHIFT
        </autogen>
        <autogen>
            __KeyToKey__
            KeyCode::O, ModifierFlag::OPTION_L | VK_SHIFT | ModifierFlag::NONE,
            KeyCode::U, ModifierFlag::OPTION_R, KeyCode::O, VK_SHIFT
        </autogen>
        <!-- Small with OPTION_L -->
        <autogen>
            __KeyToKey__
            KeyCode::A, ModifierFlag::OPTION_L,
            KeyCode::U, ModifierFlag::OPTION_L, KeyCode::A
        </autogen>
        <autogen>
            __KeyToKey__
            KeyCode::O, ModifierFlag::OPTION_L,
            KeyCode::U, ModifierFlag::OPTION_L, KeyCode::O
        </autogen>
        <autogen>
            __KeyToKey__
            KeyCode::U, ModifierFlag::OPTION_L,
            KeyCode::U, ModifierFlag::OPTION_L, KeyCode::U
        </autogen>
        <!-- Small with OPTION_R -->
        <autogen>
            __KeyToKey__
            KeyCode::A, ModifierFlag::OPTION_R,
            KeyCode::U, ModifierFlag::OPTION_L, KeyCode::A
        </autogen>
        <autogen>
            __KeyToKey__
            KeyCode::O, ModifierFlag::OPTION_R,
            KeyCode::U, ModifierFlag::OPTION_L, KeyCode::O
        </autogen>
        <autogen>
            __KeyToKey__
            KeyCode::U, ModifierFlag::OPTION_R,
            KeyCode::U, ModifierFlag::OPTION_L, KeyCode::U
        </autogen>
    </item>
</root>