Australian Honours degree for admission into European PhD programs
I can say some things about the situation in Germany, I know nothing about how it works in Belgium (Europe is diverse, and for this case, even Germany is diverse...). 

The short, but not immediately helpful answer is: It depends on many factors. I would expect that most of the time you will have difficulties going for a PhD with a Bachelor´s degree in Germany. But a general answer if this will be the case is not possible. Every university and to some extent every faculty can make their own rules, and a supervisor who really wants you in her/his group can fight for your case. If you do not have such support, your case might be doomed to fail, or you will have to take so many extra courses that it would be easier to take a Master´s degree. Because the outcome of such a discussion (usually on faculty level) is hard to be predicted the people you contacted cannot say much more than what you found online. So you should find a potential supervisor who is convinced of you as a PhD student. 

One of the reasons is that the Bachelor/Master system has no long tradition in Germany. Bachelor´s and Master´s degrees first appeared around 10-15 years ago within the Bologna process (https://en.wikipedia.org/wiki/Bologna_Process). In most cases, there was a hard transition from a diploma degree (without any 'intermediate' degree comparable to a Bachelor´s degree) taking 4-5 years to finish to a Bachelor/Master program taking 5 years in total. The old diploma programs were more or less copied to the new program. Therefore, it is still rather unusual to finish with a Bachelor´s degree only, and practically everybody going for a PhD has a Master´s degree. You come from another part of the world with another tradition, but this is what you have to understand for Germany. 

You can be very happy that the Bologna process exists, otherwise it would be much harder for you. My father came to Germany in the 1970s with a B.A. which was unheard of, so faced difficulties more or less throughout his career. And to be honest: I, as an example for somebody rooted in German academia, do not know what an Australian Honours degree is and how it compares to a Bachelor's or Master's degree.