Adding sheets to older prints help

[Miyamoto12]

Is it possible for me to add a drawing sheet to an existing .prt file that already has a blueprint? I've already made the drawing sheet and would like to paste it in the existing file, but when I do all the dimension become disassociated (dotted lines). I know this is because those measurements are dependent on the model from the other .prt file, but I've tried importing the geometry in the old file into the new and it creates a mess. What's the easiest way to add a sheet to an older print, when you've already made it from another identical model?