Pork in foil | Juicy and tasty

pork 1kg (2.2lb)
juice of 1/2 lemon
oil 100ml (3.4oz)
1-2 Tsp of mustard
soya sauce 100ml (3.4oz cup)
2 tomatoes
mushrooms 200g (7oz)
4 cloves of garlic
cheese 200g (7oz)
parsley
5 potatoes
2 carrots
salt
1 Tsp of butter
some milk