Well, just send the upk file with the map, I don't understand where is you problem here... :\ By the way, be sure that the packages are in the content folder of the udk at least (can be in sub-folder of the "Content" folder).
if you want to send him the map and have it all work you will need to send him all the upk's the map uses content from, and all of this should be in the udk content folder.