android - Sherlock action bar action icons have wrong size / dpi

Question

I use SherlockActionBar to get the ICS look to older devices. On a Optimus Black P970 (800x480) I get different icon sizes. The 2nd and 4th icon are hdpi icons, so this is correct but why does sherlock provide mdpi/ldpi icons?

<item
    android:id="@+id/menu_save"
    android:title="@string/menu_save"
    android:icon="@android:drawable/ic_menu_save"
    android:showAsAction="always" />

<item
    android:id="@+id/menu_today"
    android:title="@string/menu_today"
    android:icon="@drawable/ic_menu_calendar"
    android:showAsAction="always" />