The resgen tool is not the way to go here. This creates the binary from the resx file. Rather you can manually perform the hook yourself in the express addition. "Generate Local Resource" menu command creates a resx file and in the \app_Localresources folder as well aqs adds the attributes to the page control tags for you.
For example, manually create the app_localresources folder at the right level, then use add new item to create an assembly resource file in that folder with the right convention, then add keys to it. You could then add the attributes to the control as required, or use the expressions dialog in design-view to hook up explicit expressions to resource keys.
The quick starts give you some background that can help out.