If you want your stereotyped connectors to show up when filter to toolbox is active, you need to add them to your toolbox.
If you're using the metamodel rules to define quicklinker rules instead of the spreadsheet, meaning forwards and meaning backwards allows you to create the connector in either direction. If you don't define it, you will only be able to create it in one direction. (Or if it's only valid in one direction you just get the connector type displayed in the menu)