Creates a new mobile device invitation by invitation

<mobile_device_invitation>
	<username>string</username>
	<invitation_type>DEFAULT</invitation_type>
	<login_required>true</login_required>
	<multiple_uses_allowed>false</multiple_uses_allowed>
	<expiration_date>Unlimited</expiration_date>
	<enrolled_into_site>
		<id>-1</id>
		<name>None</name>
	</enrolled_into_site>
	<keep_existing_site_membership>false</keep_existing_site_membership>
	<site>
		<id>-1</id>
		<name>None</name>
	</site>
</mobile_device_invitation>