Those useless AT guns...

[Der Landser]

Also, the question itself does provide an answer. "What do you do with all those 45mm AT guns in 1944?" Hmmm.... lets see... ;)

They were pretty much useless as the Wehrmacht quickly discovered when they began to encounter the T-34. German ATG troops called the 37mm PaK 36 the Panzeranklopfgerät (Tank Door Knocker) or Heeresanklopfgerät (Army Door Knocker) since all it seemed to be cabable of was alerting the T-34 crew to their presence. After announcing their presence, the T-34 crew focused their attentions on the poor ATG crew with devastating results.