Wellspring Magic is not working

Good morning everyone.

I’ve been re-reading the Secrets of Magic and trying to create a Wellspring Sorceror.

Details
Name: Kupima (swahili for Testing)
Ancestry: Kitsune (Empty Sky Kitsune)
Background: Merchant
Class: Sorceror (Wellspring Mage)

Now I can create the character in Pathbuilder2e.com just fine but when I try to create it in Demiplane, I get the following issue:

There are no supported Class Archetypes for your current selections. The currently supported archetypes are: Elementalist (Spontaneous Spellcasters), Wellspring Mage (Arcane/Primal Spellcasters)

So here’s the problem. Wellspring Magic states:

Wellspring Magic 1st

Prerequisites: You must have a class that casts spells with a spell repertoire.

and Elementalism states:

Elemental Magic 1st

Prerequisites: You must have a spellcasting class feature that chooses spells from the arcane or primal spell list.

so the currently supported archetypes are back to front, and so I’m not able to assign that Class Archetype.