Hello Guillaume,
Sure, I will keep you posted.
Current version of Aspose.Slides for RS supports all base MS Reporting Services functionality and works fine except several minor problems. That is finished product but in the same time library is under development. Unfortunately, dynamically resizable headers is not a standard feature and wasn’t implemented yet. We always improve quality and size of generated reports. Also we continuously extend available functionality. If you need any features urgently, we can implement it with high priority. There are some things which will be added soon: support for hidden objects, gradient fill styles, inserting images to table cells without stretching, support for “CanGrow” property for headers and footers and other improvements.