Well I wrote this:
static ConstructorHelpers::FClassFinder<UActorComponent> FlatCompOb(TEXT("Blueprint'/Game/Components/FlatComponent.FlatComponent_C'"));
FlatCompClass = FlatCompOb.Class;
UClass* baseClass = FindObject<UClass>(ANY_PACKAGE, TEXT("ActorComponent"));
if (FlatCompClass->IsChildOf(baseClass))
{
UActorComponent* NewComp = NewObject<UActorComponent>(FlatCompClass);
NewComp->RegisterComponent();
}
The path is defined, but my FlatComponent is not added as a component.