Drain both pineapple slices, and cherries, reserving their juices.
Remove ham from packaging, and rub with the seasoning packet enclosed with the ham. Place ham, flat side down in a roasting pan.
Reserve 1/4 cup of juice. Place pineapple slices with cherries in the middle of each slice (secured with tooth picks) over the surface of the ham.
Sprinkle ham with 1/4 cup brown sugar. Add remaining juices and beer to the bottom of the pan, cover tightly with foil, and bake for 1 hour.
Remove ham from oven, and place on cutting board when cool enough to handle. Pour juices into a sauce pan, add dijon and bring to a boil. Take reserved 1/4 cup of juice, and blend with corn starch. Quickly blend into boiling juices, and heat until thickened.
Carve ham into slices, removing extra fat. Place Place slices back into roasting pan, placing pineapple slices and cherries on top. Pour thickened glaze over ham, and sprinkle with remaining brown sugar.