For user control properties to appear in the design time window, you need to have "Property Let" and / or "Property Get" subroutines in your user control code for each of the properties. Which ones you have is determined by if the property in question is read only ( the Get sub ), write only ( the Put sub ), or allows both read and write.
If you want the control to save the properties, then you will also need a "PropertyBag" object.
Do a search on "Property Let", "Property Get", and "PropertyBag" to learn more.
Robert