Regarding my question, I have an OOTB control called ProjectProperty, which i can call in sharepoint like that:
<SharePoint:ProjectProperty Property="Title" runat="server" />
I want to extend this control. So i created a class which derives from this control:
public class SiteProperty : ProjectProperty
And i added some functionality in this class.
My question now is, how can I use this extended customcontrol in the MasterPage. Where or how do I say that ok this is CustomControl and it should be used?