This is what Uexküll WB der Patent- und Markenpraxis calls it. As you say it is Austria, I presume a utility model is meant (rather than, say, a continuation-in-part). You may want to call it "derivation of a utility model application", but simply "derivation" seems to be okay, too. See, e.g.
http://www.ipr-helpdesk.org/docs/docs.EN/invencionesTecnicas...
"In almost all national utility model systems, certain mechanisms connect the utility model with the patent. These mechanisms exist to prevent mistakes on the part of the inventor in applying for adequate protection: there will often be a way to transform a patent application into a utility model application and vice versa. In other cases, these mechanisms prevent the invention from being deprived of protection when the inventor does not have a clear idea of the invention's level of inventiveness. Thus, inventors are allowed to apply simultaneously for a patent and a utility model for the same invention, the registration of the utility being granted only if the patent application fails for want of an inventive step. Finally, in other cases, there is an attempt to offer the inventor full protection for the invention by obtaining a utility model registration while the patent application is pending (which, as we have said, usually takes a couple of years). This is the case of the so-called internal priority (Germany, Austria, ...) or derivation (Germany, Austria, ...)."

And http://www.european-patent-office.org/legal/national/html/en...
As regards the legal device known as "derivation" ("Abzweigung") of an application for a utility model from an EP application, see OJ EPO 1987, 175.


Just as an aside, the (German) patent attorneys I used to work for always called it "branching off a utility model", for which you can also find some googles, but I never felt entirely comfortable with it.


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Note added at 2 hrs (2006-08-02 19:54:02 GMT)
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I see Kim already posted the EPO reference ... sorry about that. But this has nothing to do with "disclosure". They're talking about patent applications that have reached a point at which it is uncertain what protection is going to be granted, if any at all. To salvage what can be salvaged, applicants may choose to file a divisional application (Ausscheidungsanmeldung) or "derive"/"branch off" a utility model application, for the reasons explained at the Austrian Patent Office website. This is (just slightly) different than if the applicant had filed a utility model application right from the start.