Hi Domenico,
Thank you for contacting Syncfusion Support.
We have prepared a Ribbon sample which tries to meet your requirement. In this sample we have populated RibbonBar with RibbonButton like your code.
Please download the sample from the below link
If your requirement different from this sample, please provide more information about your requirement. It would be helpful to resolve your problem at the earliest.
Regards,
Mariappan S.