Sadly, a number of (January) posts were lost during the forum's migration to the new server, including my note regarding the Marschfantasie. So I'll try to write it again.
To my knowledge, there's only one period source that (seemingly) credited Baumann as an author of a march fantasy over his song "Es zittern die morschen Knochen": Telefunken A 2501. This record actually contains two march fantasies, over Götz & Flex's song "Wildgänse rauschen durch die Nacht" and over Baumann's "Es zittern die morschen Knochen". However: on the record labels, the Telefunken company credited (as usual) only the authors of the original songs, and not the authors of the new arrangements. There was even a version of the labels with no composers credited; instead, both tracks were mistakenly credited as folk songs. So, the Telefunken info can't be considered reliable/definite. Of course, Baumann still might have had composed such a piece, but, with the current info, there's no real reason to believe that he did.
What adds to my suspicion is the fact that, according to F. K. Prieberg's research, Alfred von Beckerath composed a march fantasy over this song, entitled "Es zittern die morschen Knochen, Marschfantasie über ein Kampflied von Hans Baumann". The very same title appears on the Telefunken label. Prieberg did also mention Baumann himself composing such a piece, but his source for this info was the same unreliable Telefunken record.
Anyhow, without a solid confirmation from a different period source, the author of the Telefunken march fantasy should be considered unknown. The decisive info on this matter might be found in the original Telefunken recording list. Unfortunately, I only have a short version of the list at the moment, with no track authors credited. So if anyone has a complete copy of the Telefunken recording list, with authors of "Wildgänse" (mx. 22895) and "Es zittern" (mx. 22896) credited (including, hopefully, the new arrangers), please let us know.