Hi Harald,
Thank you for contacting Syncfusion Support.
We have checked your query and created the workaround sample to meet your requirement. In this sample we have set HorizontalAlignment as Center for internal Grid using VisualUtils.
On analyzing your requirement, we suggest to use our RibbonButton control which meets your requirement. We have used RibbonButton in this sample. We can show image at center in RibbonButton by setting HorizontalContentAlignment property as "Center".
Please download the sample from the below location.
Sample:
ButtonAdvExampleRegards,
Priyanga B