Bring a large pot of water to a boil, and cook the tortellini 7 to 8 minutes, or until al dente. Drain and transfer to a large bowl.
In a saucepan over low heat, simmer the milk, onion, bay leaf, cloves and nutmeg about 15 minutes. Remove from heat, and discard the onion, bay leaf and cloves.
Melt 2 tablespoons butter in a large frypan over medium heat. Stir in the red capsicum and asparagus and cook about 3 minutes. Stir in the mushrooms, and continue cooking until tender. Mix in the smoked salmon, reduce heat to low and cook until heated through.
Melt the remaining 2 tablespoons butter in a saucepan over medium heat and slowly whisk in the flour until smooth. Thoroughly blend in the warmed milk. Stir into the frypan with the salmon mixture.
Spoon the salmon and sauce mixture into the bowl with the cooked pasta and toss to coat.