As a workaround use a dimmer item and a rule:
items:
Rollershutter your_shutter_item ...
Dimmer your_shutter_item_Alexa "shutter" ["Lighting"]
rule:
rule "Shutter Alexa"
when
Item your_shutter_item_Alexa received update
then
your_shutter_item.sendCommand(your_shutter_item_Alexa.state.toString)
end