Yes the HA integration app is only for HE devices into HA. I have written an MQTT app that works either way so you will be able to bring HA sensors into HE. It uses HA statestream protocol for auto discovery of such devices in HE. It can also bring any MQTT payload into a suitable HE device.
It’s been in beta for quite some time but is about to become a release version after perhaps one final ‘check‘ release and a long overdue documentation update. It’s stable.
PS If you use NodeRED you could achieve it that way too.
