OK, here’s what I’ve found so far…
General der Panzertruppen Hermann Breith, commander of the III.Panzerkorps, Heeresgruppe SÜD
At the beginning of April 1945, the following units were under his command:
1. Volks Gebirgs Division, Generalleutnant Wittman
Kampfgruppe Krause under the command of Generalleutnant Walter Krause (SS Kampfgruppe Schweitzer was under this command)
ARKO 3 under the command of Oberst Semmer, Artillerie Kommandeur, III. Panzerkorps
Sperrverband Motschmann, formed from SS Polizeiregiment 13
Overall total confirmed troop strength .. 20,000 men
On Good Friday, 30th March 1945, SS-PzGren.A.u.E.Bataillon in Graz was alerted, and sent to the Hungarian border via civilian buses as ‘Kampfgruppe Schweitzer’. The heaviest weapons available were a few Granatwerfer. Alledgedly 6 companies in total, some of the individuals were no older than 16.
There is an account via memoir of Heinz Burbach, a former Unterscharführer of SS-A.u.E.Btl. 11, describing the counterattack to retake Rechnitz and Schachendorf starting 31 March, Russians were thrown back to the Hungarian border. Then, despite heavy Russian counterattacks, over 10 days the German defense held with 600 casualties, but the units were encircled by the enemy because neighboring units were not able to hold the line. Some of the troops had no more than six weeks prior training. The foundation of this unit were in part wounded Unterführer and men of the SS-Pz.Gren.Rgt. 23 Norge of 11. Freiwilligen Panzer Grenadier Division. After successfully retaking Rechnitz, many cases of abuse of civilians by the Russians were verified, including the rape of women and girls, as well as plunder of homes and businesses.
In the afternoon of 4 April, Rechnitz was completely encircled, upon which Sturmbahnführer Schweitzer resolved to break out of the encirclement. The breakout occurred between 6 to 9 April in the direction of the town Weiden. Schweitzer was wounded during the successful breakout, command of the unit was assigned to Untersturmfüher Hans Roller. After rest and reinforcement in the area of Hartberg, the unit was reassigned to ARKO 3 under the command of Oberst Semmer.
Schweitzer was awarded the Knight’s Cross on 14 April for his action in leading the successful attack to retake Rechnitz.
Via Generalleutnant Walter Krause’s memoirs…
As of 31 March 1945, some of the units assigned to transfer to his command arrived in Großpetersdorf prior to the attack on Rechnitz…
1 Ausbildungs Bataillon der Waffen-SS (fairly certin this was Schweitzer’s unit), approx 900 men total in 5 companies, well armed and well led, CONSISTING MOSTLY OF VOLKSDEUTSCHE FROM HOLLAND AND NORWAY, and whose leaders were all Reichsdeutsche.
1 Gebirgsjäger Ausbildungs Bataillon, approx 400-500 men, armed only with light MG’s, and no heavy weapons.
1 Gebirgs Veterinär Ersatz Kompanie, approx only 150 not combat capable older men, without MG’s
1 Kavallerie Ersatz Schwadron, approx 180 men, barely combat-capable, no MG’s
With these troops he put together the counterattack to retake Rechnitz, with a brief account of the action from April 1 to April 5.
There is only one mention in the book of Heiligenkreuz, about action around there on April 30, plus Heiligenkreuz is much farther to the south, in the Hartberg area. You can see it on the map at the bottom border of the first pic, to the left of my fingertip.
I hope this information is of help!
BTW, I just tonight read the guidelines regarding copying/posting book material, so from here on in, no more map/text pics from me. Pretty sure this book has been out of print for some time, but 'rules is rules', and now that I have read them, I will follow them...