in the thread mentioned we've established that virtually no single-engine POH (including the DA-40) mentions anything about an external power start
It's in the C172N/R/S, Archer III, Archer II, and Piper Cadet POH's, and then I only checked the ones in our club...
Doubt much of any substance is ever "established" in a forum thread... It can give you a useful hint for what info to look up in a
reliable source though...