Hi Geert,
Sorry about the late reply; my spam filter quarantined your message for some reason.
The "eidenv" command is part of OpenSC; it is not shipped as part of the official Belgian eID middleware. OpenSC does have support for Applet 1.7 eID cards, but they do not support the newer Applet 1.8 eID cards. As such, these cards are not supported
by OpenSC and by extension not by eidenv either.
If you rely on that, you will need to work with OpenSC to add support for Applet 1.8 cards to their PKCS#11 module. I did work on the beginings of this once, but have never been able to finish it due to lack of time.
Kind regards,