Can I use bookmarks/custom activity in Workflow designer?

This is sort of a noob question...

I've seen how to create an activi开发者_运维百科ty that works with bookmarks here, but how can I use this custom code as an Activity inside a workflow designer?

In Visual Studio any activity in the same solution will automatically be added to the toolbox when you open the workflow designer. If you are using self hosting or a previously created library of activities in VS2010 you need to add it to the toolbox yourselfs.