Is there any way to create a custom capistrano task for performing other actions on a scm repository?

For instance, I would like to create a task that will checkout a particular folder from my repository and then symlink it into the shared/ directory of the main project on my server.

I know this can be done by creating a task and explicity defining the "svn co ..." command along with the scm username, password, and repository location. But this would display the password in plain text. Are there any built-in capistrano variables/methods that would help in this process?