In Team Build, how to checkout and checkin a file that is not on your workspace?

I'm customizing my own Team Build workflow, and at some point within the "Run on Agent" sequence, I need to checkout a file that is not in the current workspace, edit and check in again.

I started by creating a sequence that does more or less what the default template does: CreateWorkspace, then GetWorkspace and DownloadFiles. I already have coded activities to Checkin and Checkout files. Doing some research, Mi开发者_运维百科crosoft tells you not to use CreateWorkspace:

From MSDN Team Foundation Build Activities

CreateWorkspace Activity

You will probably never need to create or modify an instance of the CreateWorkspace activity. If you are designing a build process that requires one or more additional workspaces, you must create a custom activity to accomplish this goal.

I think that's what I'm going to explore next. Does anybody have a better idea?