by Richard Oelmann.
I would imagine the reason it is not there is simply because it wasn't there before and no-one made the suggestion to include it when the new assignment module was being created. I know you can do something similar by adding a 'cover sheet' in the pdf assignment type and this is working its way into core so maybe that functionality will be part of wht gets to core and will be usable with other assignment types as well?
Otherwise it may be worth filing an improvement suggestion in the tracker.
Richard