You will NOT keep your trail foot down through impact unless you are on plane. It is impossible and you SHOULD NOT keep your trail foot down if you are coming over the top.. it could cause damage to your back, etc...
Get the club on plane - work on getting the club on plane - if trail shoulder drops through impact, rather than coming across the shot in downswing, it is very easy and you will keep your trail foot down.
Remember - trail foot coming up is an effect, not a cause.
Thanks for the responce. I can feel that move your mentioning (without club in office). Would you say the move you mention is simalar to Moe's feeling of his vertical drop????
Try to keep the lower spine in position, (your butt back - staying in the same place throughout the swing, and see if the foot stays down. Let me know what happens....Swing EASY at first to get it right.