Heres something visual for you. To prime it I close the 1-1/2" big ball valve, open the 1/4" ball valve, suck the air out, close the the 1/4" valve, then open the 1-1/2" and plug in the pump. Done. No drilling required. The pump doesn't need to sit under the sump. I think I just did that because space was tight.

http://i254.photobucket.com/albums/h...icture1342.jpg