Hi,
I have tested the RichMessageBoard by seting the ConnectionString at runtime and after a few tests i just realize that the OnInit method is being called first on the control and later on the WebPage.
For now you can use the OnPreInit method instead of the OnInit method of the WebPage to set the connection string at runtime.
I already fix this issue on the RichMessageBoard to work properly, i will be uploading the new installer in a few minutes (remember that you can download it from http://www.richercomponents.com/downloads/)
I want to thank you for your valuable observation.
cheers.