Defining custom properties for extensions in the Visualize Tab

Hello,

I just went to through the SAP HANA Cloud documentation > Visualization Extension Customizations

I followed the tutorial step by step ; the Web IDE is really great btw.

Everything works fine and I am fully able to visualize the sample bar and modify the properties in the "ComposeTab".

Now, I would like to modify the example to have some properties available in the "VisualizeTab".

For example, the standard column chart has the following customisations properties available  in the "Visualize tab":

How can I achieve the same in the sample Bar project example?

Thank you