The SDK docs say the < Extend > tag is to be inside the < Preset > tag. I believe this is incorrect as the Generic.xml has
<!-- Setup some parameters for most common uses (extending ASOBO_GIE_Base) -->
<InputEvent ID="ASOBO_GIE">
<Presets>
<Switch Param="INPUT_EVENT_TYPE">
<!-- Finite and relatively small numbers of states -->
<Case Value="INTEGER">
<Extend Target="ASOBO_GIE_Base">
<Parameters Type="Default">
<NUM_STATES>2</NUM_STATES>
<ON_STATE_CHANGED_EXTERNAL_CODE/>
Did you mean < Presets > tag?