[NTG-context] Letterhead Usage

I have created a letterhead for correspondence, but it is too unfriendly to have to include it in every time. I would like to use it as a package, but don't know if it's possible. The problem I see is that the command \setlayer must be done after the \starttext command. If it doesn't then formatting commands such as \sc will not take affect and I believe a different font is also applied. What would be a user friendly way to implement letterheads (made up using the layers functionality of context? Thanks