[SeaBIOS] How to build SeaBIOS as CSM for Tianocore?

[Rafael Send]

Hi all-
I've found only vague references to doing this (
https://www.seabios.org/Build_overview#Build_as_a_UEFI_Compatibility_Support...),
and no real guides / examples.

Before I go on a wild goose chase, has anyone tried this before?

I've tried the other way around, loading DUET from SeaBIOS, but all I get
is a brief message that's too short to read properly (but it looks like
it's loading memory locations, didn't see any errors), then I land back at
SeaBIOS.

Any pointers would be appreciated!
Cheers,
R