ACME with selfhost.de: SELFHOSTDNS_MAP + RID

[Sperber]

Setting:

• pfSense 2.6.0 with ACME package
• DynDNS via selfhost.de (with destination subdomain.tld.de)

Goal:

• pfSense/ACME with automatic update of txt values at DynDNS provider via api on certificate renewal.

Problem:

• ACME asks for a SELFHOSTDNS_MAP entry (tells me nothing, found nothing in package settings, Google has 2 entries for that)

SELFHOSTDNS_MAP must contain the fulldomain incl. prefix and at least one RID

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Current settings:
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My questions:

• what is the SELFHOSTDNS_MAP entry?
• what is meant by RID in this context?
• where do I have to enter these values?

Would be very happy if someone could help me out a bit.
Thanks in advance!